Make the Banana Cupcakes:
Sift together the flour, baking powder, baking soda and salt in a bowl.
Mix the wet ingredients -- the mashed bananas, the nondairy milk, coconut oil, sugar and vanilla -- in another bowl.
Pour the well-mixed ingredients into the dry ingredients and mix until you have a smooth batter. Do not overmix.
Line a 12-cup muffin tin with cupcake liners. Divide the batter equally between the cups. Smooth down the tops and bake in a preheated 350-degree oven for 25-27 minutes or until a toothpick inserted in the center of a cupcake comes out clean.
Remove the cupcakes to a rack, let them cool in the tin for about 10 minutes, then unmold and let them cool completely on the rack. These cupcakes are gorgeously golden.
Make the Peanut Butter Frosting:
Cream together the peanut butter, vegan butter, and coconut oil until they are smooth and fluffy, about two minutes.
Slowly add the powdered sugar, 1/2 cup at a time, and mix well after each addition. If the frosting is too stiff, you can add a little more coconut oil.
Frost the cupcakes once they have cooled completely.