Pour water into a steamer or cooking pot. Let boil.
Sift flour, sugar, and baking powder. Combine in a bowl. Mix well.
Gradually add the milk and egg while stirring. Continue to stir until the texture of the mixture becomes smooth.
Stir-in the vanilla extract, butter, and half of the cheese.
Pour the mixture into small to medium sized molds. Arrange in a steamer. Cover and steam for 25 minutes. Top each puto with the remaining cheese. Steam for 5 minutes more.
Take the steamed cheese puto out of the steamer. Let it cool down.
Gently remove the puto from the mold with the help of a spatula and serve.