For the cupcakes
．1 ½ cups all-purpose flour
．1 teaspoon baking powder
．½ teaspoon baking soda
．¼ teaspoon salt
．½ cup unsalted butter, softened
．1 cup granulated sugar
．2 large eggs
．1 teaspoon vanilla extract
．2 ripe bananas, mashed
．½ cup buttermilk

For the chocolate monkey faces
．½ cup semi-sweet chocolate chips
．1 tablespoon vegetable oil

For the banana slices
．1 ripe banana, thinly sliced