2 cups plain flour
1/2 cup cocoa
1 1/2 tsp baking powder
1/2 tsp salt
1/2 cup butter
1 cup sugar
1 large egg
1 cup milk
Preheat oven to 210 degrees. Line 2 large trays with baking paper.
Sift flour, cocoa, baking powder and salt in a bowl. Cream butter and sugar with an electric mixer until pale and fluffy. Add egg, mix well and then add dry ingredients alternating with milk, mixing gently until just combined. Drop batter 1/2 tbsp at a time about 5cm apart onto each tray. Bake for 7 mins, until springy to touch. Transfer to racks to cool, change paper and repeat until all used.
Match cakes in pairs and spread with filling before joining together.
Combine 1/2 cup butter and 1 2/3 cups icing sugar in a bowl mixing with electric mixers for about 5 mins or until fluffy. Add 1/2 tsp vanilla extract and 2 cups marshmallow cream (available in Coles/Woolies in either the baking or spread sections)