Banana Walnut Cake

Place first seven ingredients in a large mixing bowl. Beat on low speed just until combined, then on medium for 2 minutes. Pour into a greased and floured 10-in. tube pan or a 13-in. x 9-in. x 2-in. baking pan. In a small bowl, combine topping ingredients until crumbly; sprinkle evenly over batter. Bake at 350 degrees F for 45 minutes. Cool. Store well-wrapped in refrigerator. ');