In a medium sized bowl combine flour, baking soda, baking powder, and salt, whisk together until all dry ingredients are blended.
In a separate large bowl beat butter at medium speed with an electric mixer until creamy; gradually add 1 1/2 cups sugar, beating well. Add eggs one at a time, beating well after each addition. Stir in banana and vanilla.
Add the flour mixture to the butter mixture working in small batches, alternating with the sour cream, beginning and ending with the flour first. Beat on low speed after each addition.
In a separate small bowl combine chopped pecans, 2 tablespoons sugar, and cinnamon. Stir until combined. Pour half the batter or slightly less into a greased and floured bundt pan. Sprinkle with pecan mixture and then pour the remaining batter over the pecan layer.
Bake for 50-60 minutes. Cool 10 minutes on a wire rack, then remove from pan. Let the cake cool until it’s slightly warm or room temperature.
Combine sifted powdered sugar and water or milk in a medium sized bowl. With a spoon drizzle glaze over the cake.