¾ cup raw walnuts
1/3 cup dutched cocoa*
1/3 cup plus 1 tbsp bold, dark coffee, freshly brewed
3 (about 1 ½ cups) speckled, overripe bananas, mashed
¾ cup sour cream
1 tsp vanilla
1 ¾ cup plus 1 tsp all-purpose flour
1 ¼ tsp baking powder
¾ tsp baking soda
¼ tsp salt
1 stick butter, softened
3/4 cup granulated sugar
¼ cup light brown sugar
Preheat oven to 350 degrees. Spread walnuts on baking sheet and toast in oven for 5-7 minutes, or until golden brown and fragrant. Remove from oven and place in small bowl. Sprinkle with 1 tsp flour, making sure walnuts are evenly coated, and set aside (the flour helps to keep the nuts suspended in the batter). Combine cocoa with hot coffee, stir to make a paste, and set aside. In medium bowl, whisk together mashed bananas, sour cream, and vanilla. Set aside. Whisk together 1 ¾ cups flour, baking powder, baking soda, and salt. Set aside. In a separate, large bowl (or stand mixer), beat together butter and sugars for 2 minutes, until creamy. Add eggs one at a time. Add the flour mixture in halves, alternating with the banana mixture, and stir until just combined. Stir in walnuts. Pour half the batter into a separate bowl and stir to combine with cocoa mixture. Spoon the chocolate and banana batters into a buttered 9x5x3-inch loaf pan** so that they alternate like a checkerboard. It doesn’t have to be perfect, but should look kind of like this:
Use a spoon or spatula to gently fold the batters into a marbled swirl. Bake for 60-70 minutes, or until a toothpick placed in the center of the loaf comes out clean, with crumbs attached. Let cool for 10 minutes, then turn out to cool completely on rack. Serve at room temperature–bread tastes best when cool, particularly on the second day. Store in an airtight container. Bread will keep for up to 4-5 days.
*It is very important that you use dutched cocoa, and not regular unsweetened cocoa, for this recipe. This is because dutched cocoa has been alkalized, and therefore has a neutral pH in comparison to normal cocoa, which is more acidic. This means that dutched cocoa reacts differently, and cannot be substituted if you’d like to replicate my results. While technically, it’s OK to substitute dutched cocoa powder with unsweetened cocoa powder (though not the other way around!), I still would not suggest it for this loaf. The thing is, I came up with this recipe specifically with dutched cocoa in mind. Here’s why: it smells intoxicatingly wonderful, and is one of my favorite things.
**Butter that loaf pan well, for there is nothing more disappointing than watching parts of your banana bread stick to the pan while other parts acquaint themselves with the counter, the floor, and any hungry pets who may have been weaving figure eights round your legs hoping you’d drop something. I know this from experience.