Cooking spray or softened butter and granulated sugar, for the pan (optional)

1½ cups/218g all-purpose flour

1 teaspoon baking soda

¾ teaspoon/3g kosher salt

1 stick/4 ounces/113g butter, at room temperature

½ cup/110g granulated sugar, plus 2–3 tablespoons

½ cup/110g light brown sugar

2 large eggs

3 very ripe bananas/320g, peeled and mashed,

plus 1 banana, halved lengthwise

½ cup/100g mascarpone, whole-milk yogurt, or sour cream

Preheat the oven to 350°F. Line a 9 × 4-inch loaf pan with parchment paper. (Alternatively, spray a 9 × 4-inch loaf pan with cooking spray or grease with softened butter and sprinkle the interior with enough granulated sugar to coat, tapping out excess—this will give you a slightly sweeter banana bread with a crunchy crust.)

In a medium bowl, whisk together the flour, baking soda, and salt.

3 In a stand mixer fitted with the paddle (or in a medium bowl with an electric hand mixer), cream the butter, ½ cup/110g sugar, and the light brown sugar together until light and fluffy, 3–5 minutes. Add the eggs, one at a time. Beat until light and fluffy, another 3–5 minutes. Slowly add the flour mixture, scraping down the sides of the bowl until everything is mostly incorporated (do not overmix).

4 Add the mashed bananas and mascarpone and mix until well blended, making sure to get all the batter at the bottom of the bowl. Transfer the batter to the prepared loaf pan, top with the halved banana, cut-side up, and sprinkle with the remaining 2–3 tablespoons sugar.

5 Bake until the bread is puffed up, golden brown, and starting to pull away from the sides of the pan, 1 hour 10 minutes to 1 hour 20 minutes. (Yes, this bakes for a long time—loaf cakes, especially very moist ones, take awhile. Do not rush it or it will almost certainly collapse on you!) Let cool completely before slicing or wrapping for later.