Preheat your oven to 160°C Fan/180°C/350°F/Gas Mark 4 and grease and line two 8" cake tins.

In a large bowl, mix the butter and caster sugar until fluffy.

Add the eggs, orange extract, and milk, and whisk until fully incorporated.

Gradually add the self-raising flour, cocoa powder, and baking powder, whisking until no flour remains.

Divide the mixture evenly between the tins.

Bake for 30-35 minutes or until a skewer inserted in the middle comes out clean.

Allow the cakes to cool either in the tins or on cooling racks if removed from the tins.

Mix the butter, cocoa powder, and icing sugar until they start coming together.

Add the orange extract and milk, and continue mixing until the mixture becomes smooth.

If your cakes have domed on top, level them off using a cake leveler or a serrated knife.

Place one of the sponges on your serving plate or cake stand.

Pipe or spread a generous layer of the mocha buttercream onto it.

Gently place the other sponge on top and cover it with the remaining mocha buttercream.

Decorate with pieces of Terry’s Chocolate Orange and sprinkle some orange sprinkles if desired.

Store the leftover cake in an airtight container in a cool place for 2-3 days.