Surprise your guests with these cute fudgy chocolate cupcakes. They may look like pure chocolate on the outside, but inside is a surprise zingy slime-like lime curd filling. They’re a simple Halloween treat that are perfect for a party. It might be a good idea to hand them out with a plate, as they are quite messy to eat!

For the chocolate cake:

1. Preheat the oven to 180^oC/350°F/gas 4.
2. Line a 12 hole cupcake tray with cases.
3. In a saucepan put the chocolate, milk and 75g of sugar. Put on a gentle heat. Heat until the chocolate has melted and the ingredients have mixed together. Set aside to cool.
4. In a bowl beat the butter and remaining 175g sugar until creamy. Mix the eggs in one at a time. Then mix in the vanilla extract and chocolate milk.
5. Sift the plain flour, cocoa powder and bicarb into the bowl. Fold them into the mixture until there are no remaining lumps of flour (whisk the mixture to get rid of any last lumps).
6. Divide the mixture between the cupcakes cases, and then bake in the oven for 20 minutes, or until an inserted skewer comes out clean. Remove and leave to cool on a wire rack.

For the lime curd:

1. Bring a small pan of water to a gentle simmer.
2. In the large glass bowl put the ¾ of the lime zest (saving the remaining ¼ for the icing) and the rest of your curd ingredients. Whisk them together and then put the bowl on top of the pan of simmering water. Make sure the water doesn’t touch the bottom of the bowl.
3. Stir the mixture constantly until it coats the back of the spoon, and you can drag your finger through the coating without the two halves coming together. This should take about 20 minutes. Make sure the mixture doesn’t boil or it will curdle. Remove the pan from the heat, and then tip the curd into another bowl. Leave it to cool completely.

For the icing and eyeballs:

1. When the cakes and curd are completely cool, make the eyeballs. Divide your white fondant icing into 24 equal pieces. Roll the icing between your hands to create spheres. If the icing is too hard stick it in the microwave on a medium heat for 15 seconds. Use the black icing pen to pipe pupils onto the eyeballs.
2. Then make the chocolate icing. Melt the chocolate, and then beat it together with the butter. Add in the icing sugar and beat to create a thick paste. Add the milk and the remaining lime zest from the curd. Beat until you have a soft spreadable icing.

Assembly:

1. Using an apple corer, make a 1.5cm hole in the centre of your cakes. Pour the lime curd into the hole. You will have plenty leftover – suggested usages are spreading it on toast, or putting it on the top of your porridge.
2. Spread the icing on top of the cakes with a palette knife. Stick two eyeballs onto the top and pipe on a mouth using the black icing pen.