Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, line a 8" square tin with greaseproof or 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
Add the plain flour and mix in, then mix in the dark chocolate chips
Tip the mixture into the tin and press it down with your fingers (or the back of a spoon) until compact and even
Bake the shortbread biscuit base for 20-25 minutes, until lightly golden, then leave to cool fully in the tin
To make the caramel, put all of the ingredients (except the orange extract) into a pan on a low heat and stir until everything is melted together
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 instruction 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 orange extract. Then pour it over the shortbread base
Put into the fridge to set for at least 2 hours, or overnight if you prefer
Melt the chocolate in the microwave. Blast for 30 seconds, then stir, then blast in 10 second intervals stirring between each one until melted
Pour the chocolate over the caramel and smooth it out, tap the tin onto your work surface a few times to remove any air bubbles and to create an even surface
Place the Jaffa Cakes into the chocolate and press in, you may need to cut some in half to fill the top completely
You can set the chocolate in the fridge for a quicker result, or leave at room temperature to set
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
For the shortbread base, the butter will need to be at room temperature before you start making it.
For the best flavour, make sure to use a good quality orange extract and not an essence.
I used unsalted butter for this recipe, and I really recommend using proper butter (not a baking spread) if you can for the best flavour.
I use granulated sugar for the caramel, but you can also use caster sugar (superfine sugar).
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 golden syrup online from Amazon. 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!
I use dark chocolate chips for the shortbread base and the chocolate topping, but you can use milk or even white chocolate if your prefer.
For more answers to Millionaire's Shortbread questions, check out my classic 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: