Puto is pronounced "poo too" in most Filipino dialects. There are many ways to make it as there are many variations. From family to family, they taste similar even if the recipes vary.
In a saucepan or microwave, melt the butter.
In a big bowl, combine the 3 cups Bisquick, 1 1/2 cups sugar, 1 cup whole milk, and 3 eggs. Add the melted butter and 1 tsp of vanilla extract. Mix with a ladle by hand or with a mixer. The mix doesn't have to be thorough, the batter can be lumpy.
You can pour the batter into cupcake paper or tin foil cups. If you pour batter into muffin cups or in a round 8 inch or 9 inch bake pan, spray or rub the pans with cooking oil or butter. The pour should be about halfway in the cups or pans.
Steam the puto in a steamer for 15 minutes or until it has rose like a cake. This version of puto is a cakey or spongy type. Continue to cook puto until there is no more batter.
After the puto is done, let it sit for a few minutes to cool. Spread some butter or margarine into the still warm puto to your taste. (Liberal amounts are preferred). Let the butter melt into the puto.