Directions:
Preheat oven to 350F. prepare a round Bundt baking pan. Sift flour and baking powder into a small bowl.
In a medium bowl, beat egg and sugar until tripled in volume. Gently, fold flour mixture into egg batter. Drizzle in melted butter and vanilla, fold gently. Add mashed banana, mix well.
Pour cake batter into prepared pan. Bake for 25-30 minutes.