Pre-heat your oven to 350 degrees. Grease a 9 inch round or square baking pan.

Using a large bowl, beat the butter and sugar together until smooth. Add the eggs, one at a time, beating well after each addition.

In a small bowl, mix the sour cream and baking soda together, STIR the sour cream into the butter mixture until well incorporated.

STIR the mashed bananas into the butter mixture until well combined. Mix the flour and baking powder together, STIR the flour/baking powder into the butter mixture. STIR in the vanilla. Pour the batter into your prepared baking dish, smooth to the edges of the pan. Combine the topping ingredients in a small bowl, mix together and sprinkle over the batter evenly.

Bake at 350 degrees for 30 – 35 minutes or until a toothpick inserted in the center comes out clean. Remove from the oven to a cooling rack, serve warm or cooled.