Cinnamon Streusel Banana Bread

Preheat oven to 350°F. Lightly coat a 9-by-5-inch loaf pan with cooking spray. Whisk mashed bananas, oil, 1/3 cup brown sugar, eggs and vanilla together in a medium bowl until smooth.

Whisk 1 cup whole-wheat flour, all-purpose flour, baking soda, salt and baking powder together in a large bowl until well combined. Make a well in the center of the flour mixture and add banana mixture; fold until just combined. Pour half of the batter (about 2 cups) into the prepared loaf pan, spreading into an even layer.

Whisk walnuts, melted butter, cinnamon and the remaining 2 1/2 tablespoons brown sugar and 2 tablespoons whole-wheat flour in a medium bowl until combined. Sprinkle the streusel in an even layer over the batter in the pan. Pour the remaining batter (about 2 cups) over the streusel; spread into an even layer, covering the streusel entirely.

Bake until a wooden pick inserted in the center comes out with a few moist crumbs, about 1 hour. (Cover with foil halfway through cook time to prevent overbrowning, as needed.)

Let cool in the pan on a wire rack for 15 minutes. Carefully remove from the pan and cool slightly on the rack, about 45 minutes. Slice and serve warm or at room temperature. Additional reporting by Carrie Myers, M.S. and Linda Frahm