BA's Best Banana Bread

Preheat oven to 350°. Lightly coat an 8½x4½" loaf pan with nonstick vegetable oil spray and line with parchment paper, leaving generous overhang on long sides. Whisk 1½ cups (188 g) all-purpose flour, 1¼ tsp. baking soda, and ¾ tsp. Diamond Crystal or ½ tsp. Morton kosher salt in a medium bowl to combine.

Using an electric mixer on medium-high speed, beat 1 cup (200 g; packed) dark brown sugar, ⅓ cup mascarpone, plain whole-milk Greek yogurt, or sour cream, and 4 Tbsp. unsalted butter, room temperature, in a large bowl until light and fluffy, about 4 minutes. Add 2 large eggs, one at a time, beating to blend after each addition and scraping down sides and bottom of bowl with a rubber spatula as needed.

Reduce speed to low, add dry ingredients, and mix until just combined. Add 4 large very ripe bananas, peeled, mashed (about 1½ cups), and mix until just combined. Fold in ½ cup chopped bittersweet or semisweet chocolate and/or ½ cup chopped raw walnuts if using with spatula. Scrape batter into prepared loaf pan; smooth top.

Bake bread until a tester inserted into the center comes out clean, 60–65 minutes. Transfer pan to a wire rack and let bread cool in pan 1 hour. Turn out bread onto rack and let cool completely (if you can resist) before slicing.