Brown Butter Banana Loaf with Cocoa Streusel Center

Steps

1. Heat the oven to 350°F (175°C). Brush a 9x5-inch loaf pan with the canola oil and line it with a parchment sling.
2. Make the brown butter: melt 90 g of the butter in a small saucepan over medium heat, swirling, until it smells nutty and the solids turn golden brown, 4–5 minutes. Pour it into a large bowl and cool 10 minutes. Set the remaining 20 g of butter out to soften for the streusel.
3. Make the cocoa streusel: in a small bowl, rub together the softened remaining 20 g of butter, 30 g of the brown sugar, the unsweetened cocoa powder and the walnuts until clumpy. Set aside.
4. In a medium bowl, whisk the flour, baking soda, salt and cinnamon.
5. Into the cooled brown butter, whisk the remaining 120 g of brown sugar, then the eggs one at a time, the mashed banana, the Greek yogurt and the vanilla.
6. Fold the flour mixture into the banana mixture just until no dry streaks remain.
7. Spread half the batter in the pan, scatter all the cocoa streusel evenly over it, then spread the remaining half of the batter on top.
8. Bake 55–65 minutes, until a toothpick in the center comes out clean (a little melted streusel is fine). Tent with foil after 40 minutes if browning fast.
9. Cool in the pan 15 minutes, lift out by the parchment and cool completely on a rack, about 1 hour, before cutting into 12 slices.