Easy Vanilla Sponge Cake Recipe

Ingredients:
1 and 1/3 cup of all-purpose flour
1/2 tsp of baking powder
1/4 tsp of salt
1/2 tsp of white vinegar
3/4 cup of Confectioner's sugar.
4 tbsp of melted butter.
4 tbsp of milk
1 tsp of vanilla essence