Variations: Once you get the basic recipe right, you can try any number of variations. For Vanilla Sponge, simply add 1 tbsp of vanilla extract to the milk or one scraped vanilla bean. For chocolate sponge cake, add 3 tbsp of cocoa powder to the dry ingredients. For berry or Fruit Sponge cake, add chopped berries/fruit or reduced puree/jam to the milk. For nut-based Sponge Cake, add roasted and chopped nuts or nut butter/paste to the ready batter. For orange and cinnamon Sponge Cake, add 2 tbsp of cocoa powder, orange zest, and one-fourth tsp of cinnamon powder. For Coffee Cake, add 2 tbsp of cocoa powder and 1 tsp of instant coffee powder to the dry ingredients. For Lemon Cake, add lemon juice and lemon zest to the batter.