Mint Chocolate Aero Millionaire's Shortbread is a divine combination of a buttery shortbread base stuffed with Aero chocolate pieces, a gorgeous golden caramel filling, and a topping of smooth milk chocolate with more yummy Aero chocolate! These caramel slices are so yummy, and full of delicious mint chocolate flavour.
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Ingredient Tips & Equipment Information
- Make sure your butter is at room temperature before you start baking the shortbread.
- I used unsalted butter for both the shortbread and caramel layers. You can use salted butter if you like, it won't make it taste salty, instead it will balance out the sweetness. However, I do prefer to use unsalted butter and add my own salt as then I can control the salt levels. You can also use a baking spread, but butter tastes much better in my opinion. It's not that baking spread tastes bad, just that real butter is richer and creamier.
- You must use plain flour (also known as all purpose flour) for the shortbread, self raising flour will make the shortbread rise, which you don't want to happen.
- You must use sweetened condensed milk for the caramel layer, evaporated milk will not work.
- I use granulated sugar for the caramel layer, but caster sugar (also known as superfine sugar) works well too.
- Golden syrup is sold all over the world, so check the international section in your supermarket if you’re not based in the UK. You can also buy it online from Amazon (see link in the recommend equipment and ingredient section). If you can’t get hold of it, light corn syrup is the closest thing to it. You can also use light brown sugar, your caramel will look different and have slightly different texture – but it will still be delicious! Check the recipe notes for details.
- You can use any kind of chocolate for the topping. Milk chocolate is the traditional option, but dark and white chocolate work well too. Pick any chocolate that is good quality and that you like the taste of, I'd advise avoiding cooking or baking chocolate as it doesn't taste great.
- For more answers to Millionaire's Shortbread questions, check out my original Millionaire's Shortbread recipe!
- Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
- For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.
For the full recipe with measurements, head to the recipe card at the end of this post.
How to make Mint Chocolate Aero Millionaire's Shortbread
To make the shortbread, mix the butter and caster sugar together, add the vanilla extract and mix it in. Next, add the plain flour and salt, mix to form a rough dough. Add the chopped up Aero chocolate and mix briefly until evenly distributed.
Then use your fingers, or the back of a spoon, to press the dough into the tin in an even layer, bake it for 20-25 minutes until lightly golden.
For the caramel layer, melt butter, sugar, golden syrup and condensed milk together in a pan on a low heat. Then boil it for around 6 minutes on a gas hob (or simmer for 10-12 minutes on an induction hob), stirring it constantly, until it is dark golden and thick. Mix in the vanilla extract. Pour the caramel over the shortbread and put it in the fridge to set. Once the caramel is set, pour melted milk chocolate over the top. Then melt the white chocolate and stir in green food colouring, swirl it into the milk chocolate. Decorate with Aero chocolate and Aero bubbles. Leave the chocolate to set at room temperature before slicing.
For the full recipe with measurements, head to the recipe card at the end of this post.
How do you cut millionaire's shortbread neatly?
To cut millionaire’s shortbread into neat slices, it is best to do this when it is at room temperature. If you do it straight from the fridge, the chocolate on top could crack, and will be quite solid so will press into the caramel causing it to oooze out. At room temperature, and using a large sharp knife (ideally a knife that is bigger in length than the length of the shortbread), and gently sawing through the chocolate, then pushing through the other layers, works well for me.
What size tin do you need for this recipe?
This recipe is for an 8" or 20cm square tin, it need to have deep sides, at least 2". If you want to use a 9" or 23cm square tin, I would recommend increasing the ingredient amounts by 25%.
What is the best way to line the tin?
I find that greasing the tin very lightly, only just enough to help the baking paper stick to it, then lining with non stick baking paper is the best way to ensure you can remove this bake easily from the tin. You should also leave an overhang of baking paper, about 1" taller than the tin. This is so you can grasp it to pull the shortbread out of the tin.
Can this recipe be made gluten free?
Yes! To make this recipe gluten free you will need to replace the plain flour in the shortbread with a gluten free plain flour blend. You may also like to add ¼ tsp xanthan gum for better texture. I would also recommend that you check the packaging of everything you're using in the recipe in case of cross contamination. And especially if you're serving this to someone with an allergy or intolerance.
Can this recipe be made dairy free?
To make this recipe dairy free, replace the butter in the shortbread and caramel with a dairy free version. I recommend a dairy free butter block, like Flora Plant or Stork Baking Block. You will also need to use a dairy free condensed milk, Carnation and Nature's Charm are brands I know of. Or you can try my Vegan Millionaire's Shortbread recipe! I would also recommend that you check the packaging of everything you're using in the recipe in case of cross contamination. And especially if you're serving this to someone with an allergy or intolerance.
Do you need an electric mixer to make this recipe?
While it is easier to make the shortbread base in an electric stand mixer with the paddle attachment, you can absolutely make it by hand with a wooden spoon and some elbow grease! For the caramel layer and chocolate layer, no electric mixer is required.
How should it be stored and how long does it last for?
It can be stored at room temperature in an airtight container for 2 weeks (although it never lasts that long in my experience! It gets eaten up too fast!) If the caramel hasn't been boiled for long enough and is too soft, then you may need to store it in the fridge to firm it up.
Can you freeze Millionaire's Shortbread?
Yes! Wrap it well in cling film, or place in a freezer bag or tupperware container. It can be frozen for up to 3 months. It is bet freeze it sliced, then you can easily defrost a piece or two at a time. Place small squares of baking paper between each square to stop them from sticking together. Defrost at room temperature, I usually leave it on the kitchen counter for an hour or so.
Do you need a sugar or candy thermometer to make the caramel?
They can be helpful but it is not essential. I never use one, I go off of the amount of time the caramel has been boiling for and how it looks. I boil my caramel for around 6 minutes on a medium heat until it has thickened and darkened in colour. If you want to use a sugar or candy thermometer, you want the caramel to reach 107C/225F.
More tips for making the Mint Chocolate Aero Millionaire's Shortbread:
- You could use any type of mint chocolates to decorate the millionaire's shortbread, such as matchmakers or After Eights.
- I used granulated sugar for the caramel, but you can also use caster sugar.
- The green coloured white chocolate on top is optional.
Troubleshooting
My number one tip for getting the best results is to read through this whole page of tips and recommendations before starting, and follow the recipe exactly. If you have any questions about this recipe, or if something went wrong and you need help, please use the comment form below and I will get back to you. You can also get in touch with me on my Twitter, Instagram or Facebook. I'd love to hear from you!
Recommended equipment & ingredients
- Mixing bowls
- 8″ Square tin
- Measuring spoons
- Cooling rack
- Kitchen scales
- Electric hand mixer
- Piping bags
- Stand mixer
- Golden syrup
- Green food colouring
- Aero bubbles
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Mint Chocolate Aero Millionaire's Shortbread
Ingredients
For the shortbread
- 175 g Butter unsalted, softened
- 80 g Caster sugar
- 1 tsp Vanilla extract
- 225 g Plain flour
- ⅛ tsp Salt
- 100 g Aero chocolate chopped up
For the caramel
- 170 g Butter unsalted
- 75 g Granulated sugar
- 80 g Golden syrup
- 397 g Condensed milk
- 1 tsp Vanilla extract
For the decoration
- 225 g Milk chocolate
- 25 g White chocolate
- Green food colouring
- 45 g Aero chocolate
- 130 g Aero Bubbles
Instructions
- Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, line a 8" square tin with baking paper. I grease the tin first with a little butter to help the paper stick to it
- To make the shortbread base mix the caster sugar and butter together into a bowl until creamy, ideally using an electric stand mixer with the paddle attachment, this takes 2-3 minutes. Add the vanilla extract and mix in
- Add the plain flour and salt, and mix in. If using a stand mixer, you may need to scrape the bowl down to make sure all of the flour is mixed in
- Add the chopped up Aero chocolate and mix briefly until evenly distributed. Tip the mixture into the tin and press it down until compact and even. I find it easier to do this with my fingertips, but the back of a spoon also works
- Bake the shortbread biscuit base for 20-25 minutes until lightly golden around the edges, then leave to cool fully
- To make the caramel, put all of the ingredients into a pan on a low heat and stir until everything is melted together and the sugar has dissolved
- Bring the mixture to the boil, stirring continuously, and let it boil for 5-7 minutes until thick and golden. I boil mine for 6 minutes. (This instructions is for gas hobs, for induction hobs, I find that simmering for 10-12 minutes works best) Take the mixture off the heat and stir in the vanilla extract. Then pour into the tin over the shortbread base
- Put into the fridge to set for at least 2 hours, or overnight. Remove from the fridge and melt the milk chocolate in the microwave. Blast for 30 seconds, then stir, then blast in 10 second intervals stirring between each one until melted
- Pour the milk chocolate over the caramel and smooth it out, tap the tin onto your work surface a few times to remove any air bubbles. Melt the white chocolate in the same way and add green food colouring. Put spoonfuls of the white chocolate onto the wet milk chocolate, then use a cocktail stick to swirl it around. Press the Aero chocolate chunks and Aero Bubbles into the wet chocolate. Leave to set at room temperature
- The best way I've found to slice it is to firstly make sure that the chocolate has set and that it is at room temperature. If the millionaire's shortbread is cold, the chocolate is very likely to crack as you slice it. Secondly, use a very sharp knife that is longer than the shortbread. This means you can slice through it in one motion. If you like you can gently score the chocolate on top to work out the sizes of the squares first. Then, with an even pressure, gently saw the knife through the chocolate, then push it through the caramel and shortbread
- Store any leftovers in an airtight container at room temperature for 5-7 days, kept in the fridge it will last for up to 2 weeks
Notes
- Make sure your butter is at room temperature before you start baking the shortbread.
- I used unsalted butter for both the shortbread and caramel layers. You can use salted butter if you like, it won't make it taste salty, instead it will balance out the sweetness. However, I do prefer to use unsalted butter and add my own salt as then I can control the salt levels. You can also use a baking spread, but butter tastes much better in my opinion. It's not that baking spread tastes bad, just that real butter is richer and creamier.
- You must use plain flour (also known as all purpose flour) for the shortbread, self raising flour will make the shortbread rise, which you don't want to happen.
- You must use sweetened condensed milk for the caramel layer, evaporated milk will not work.
- I use granulated sugar for the caramel layer, but caster sugar (also known as superfine sugar) works well too.
- Golden syrup is sold all over the world, so check the international section in your supermarket if you’re not based in the UK. You can also buy it online from Amazon (see link in the recommend equipment and ingredient section). If you can’t get hold of it, light corn syrup is the closest thing to it. You can also use light brown sugar, your caramel will look different and have slightly different texture – but it will still be delicious! Check the recipe notes for details.
- You can use any kind of chocolate for the topping. Milk chocolate is the traditional option, but dark and white chocolate work well too. Pick any chocolate that is good quality and that you like the taste of, I'd advise avoiding cooking or baking chocolate as it doesn't taste great.
- For more answers to Millionaire's Shortbread questions, check out my original Millionaire's Shortbread recipe!
- Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
- For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.
- If you can't get hold of golden syrup you can make the caramel in the same way using these ingredients:
- 150g Butter
- 75g Caster sugar
- 75g Light brown sugar
- 397g Can of condensed milk
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