Halloween Slime Cupcakes

18/10/2017 by thebakingexplorer 33 Comments

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I absolutely love Halloween and all the spooky themed food that comes with it. These Halloween Slime Cupcakes fit the bill perfectly as they look rather scary with their black "burnt" sponge, bright green "toxic" buttercream and creepy candy eyes, but don't be fooled - they taste absolutely yummy! Once you bite into their menacing exterior you'll find gooey "radioactive" slime inside. I used green coloured custard to create this effect, but you could use strawberry jam for a "blood and guts" theme inside too. Kids and adults alike will love making these fun slime cupcakes to disgust and delight their family and friends over the Halloween season!

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Ingredient Tips & Equipment Information

Make sure all your ingredients (particularly the butter and eggs) are at room temperature before you start baking.
For the best results, use good quality professional food colouring. My favourite brands are Pro Gel and Sugarflair.
I use a baking spread for the cupcakes and unsalted butter for the buttercrream.
I got the candy eyes in my local supermarket and they are pretty widely available around Halloween, but you can purchase them online too. Do check the ingredients if you are vegetarian or if you have any allergies as some can contain insect derived food colourings, egg white or milk powder. Or you can make your own by melting some dark chocolate and piping a small circle onto a white chocolate button.
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 Halloween Slime Cupcakes

To make the cupcakes, mix together butter and caster sugar. Then add eggs and vanilla extract, and whisk in. Next, add self raising flour and black food colouring and mix in. Divide the batter between the black cupcake cases. Bake for 25-30 minutes, use a thin skewer or a cocktail stick to check they are done as you won't be able to tell by the colour!

When the cupcakes are fully cooled, use a cupcake corer or a knife, to make holes in the middle of each cake. Add a little bit of green food colouring to the custard, then spoon it into each cupcake. To make the buttercream, mix together the butter and icing sugar. Add the vanilla extract, milk and the green and yellow food colourings until you have a nice bright green colour. Pipe it onto the cupcakes then decorate with the candy eyes and sprinkles.

For the full recipe with measurements, head to the recipe card at the end of this post.

What is the best food colouring to use?

I recommend using a professional grade food colour for the best and spookiest results! I used Sugarflair Black Extra for the cupcakes. For the buttercream, I recommend either Pro Gel Lime Green, or a mixture of Sugarflair Party Green and Sugarflair Melon Yellow. There are lots of other good food colouring brands, such as Colour Mill and Americolor. You can buy them all easily online.

What else can you fill the cupcakes with?

I chose to fill the cupcakes with tinned custard that I coloured green with food colouring. You could also use lime or lemon curd or lime marmalade, and again add some food colouring to them for the slime effect. You can of course leave the cupcakes unfilled if you prefer.

How long do the cupcakes last for and can they be frozen?

The cupcakes will last for 2-3 days in an airtight container in a cool place. You can freeze both the cupcakes and the buttercream. To freeze them separately, wrap the cupcakes well in cling film or put them in an airtight container. The buttercream can be frozen in a sealed tub. To freeze them decorated, freeze the cupcakes on a plate until frozen solid, then carefully wrap in cling film. Remove the cling film when you take the cupcakes out of the freezer to defrost, as if they defrost with it still on it could damage the buttercream.

Can you make the cupcakes with plain/all purpose flour?

Self raising flour, which is very commonly used in the UK where I am based, already contains a raising agent and a little salt too. Therefore if you want to swap it for plain or all purpose flour, you will need to add some additional baking powder and also a little salt if you like. Some people like to add salt to cake recipes and some don't, so I'll leave that up to you as it won't affect the bake. The general advice is to add 2 teaspoons baking powder (a measuring teaspoon, not the kind you stir your coffee with) per every 200g plain or all purpose flour. So for this recipe you'd need to add 1 + ½ teaspoons baking powder. Please note, I have not tested this recipe using plain or all purpose flour.

Is butter or a baking spread better for cupcakes?

I prefer to use a baking spread (my preferred brand is Stork) for cupcake and cake sponges. I find that they are easier to use and they make the sponge rise more. You can also use most baking spread straight from the fridge, which is handy during a last minute baking emergency!

Should you use salted or unsalted butter for cupcakes?

I always use unsalted butter and baking spread for baking. This is because if you want to add salt to your recipe, you then have complete control of the salt level. Lots of people add salt to enhance the flavour of baked goods, so when you do this you want to know exactly how much you're adding. I personally prefer not to add salt to cakes and cupcakes. However, using a salted butter or baking spread will not affect the bake negatively and won't make it taste salty.

Can the cupcakes be made gluten or dairy free?

Yes! For gluten free you can replace the self raising flour with a gluten free self raising flour blend. If you only have a gluten free plain flour blend, you will need to add baking powder. The general advice is to add 2 tsp baking powder per 200g flour, so for this recipe you'd need to add 1 + ½ teaspoons baking powder. You may also like to add ¼ tsp xanthan gum for better texture. For a dairy free version, use a dairy free baking spread for the cupcakes and the buttercream. If you are using candy eyes, check the labels as some can contain milk powder. Please check the labels of everything you use if serving to someone with an allergy or intolerance.

More tips for making the Halloween Slime Cupcakes:

I used a Jem 1E nozzle to pipe the buttercream onto the cupcakes, but you can use any nozzle you prefer or spread it on with a spoon.
You can decorate the cupcakes with any Halloween themed sprinkles you prefer.

Troubleshooting

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!

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