BA's Best Banana Bread

Nonstick vegetable oil spray

all-purpose flour

baking soda

kosher salt

(packed) dark brown sugar

mascarpone, plain whole-milk Greek yogurt, or sour cream

unsalted butter, room temperature

large eggs

large very ripe bananas, mashed (about 1½ cups)

chopped bittersweet or semisweet chocolate (optional)

chopped walnuts (optional)