1 stick butter, room temperature
3/4 cup sugar
1 egg
1 teaspoon vanilla extract
1 1/2 cups mashed bananas (3-4 ripe bananas)
1/4 cup sour cream
1 1/2 cups flour
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
Crumb Topping:
3/4 cup brown sugar
1 cup old fashioned oats
1/2 cup flour
1 1/2 teaspoons cinnamon
1/4 teaspoon salt
6 tablespoons butter
Preheat oven to 350 degrees. Grease a 9" square baking pan and set aside. In a mixing bowl, cream together butter and sugar on high speed for 3 minutes, until light and fluffy. Beat in egg, vanilla, banana, and sour cream until combined. In a small bowl, whisk together flour, baking powder, baking soda, and salt. Add flour ingredients to butter mixture and mix just until combined. Place into prepared baking pan and spread to edges.
To make the crumb topping, in medium bowl, combine brown sugar, oats, flour, cinnamon, and salt. Add slices of butter to mixture and rub in with fingers until crumbly. Sprinkle mixture over top of cake and lightly press. Bake for 40-45 minutes until toothpick inserted in the center comes out clean. Cool in pan and serve warm with whipped cream. Serves 9
