Ingredients
Method
- Stir the 1/3 cup flour, brown sugar, cinnamon, and salt together, then pour in the melted butter and mix until the streusel resembles wet sand. Set aside.
- Whisk the 1 1/2 cups flour, baking powder, baking soda, salt, cinnamon, and granulated sugar in a large bowl.
- Add the oil, eggs, vanilla, banana, and sour cream to the dry ingredients and stir with a spatula until no dry flour remains. The batter will be thick.
- Spread half the batter into a parchment-lined 9x5 inch loaf pan, sprinkle with half the streusel, then top with the remaining batter and the rest of the streusel. Press the topping lightly so it adheres.
- Bake at 350°F (175°C) for 50 to 55 minutes, tenting with foil if the top browns too quickly. A toothpick inserted in the center should come out with a few moist crumbs.
- Cool in the pan for 15 minutes, then lift the cake out by the parchment and set it on a wire rack to cool completely before slicing.
Notes
Let the cake cool fully for the cleanest slices. If you skip the parchment, grease the pan well and let the cake cool an extra 10 minutes before turning it out.
