Preheat oven to 350°. Lightly coat a loaf pan with nonstick spray and line with parchment paper. Whisk flour, baking soda, and salt in a medium bowl.
Using an electric mixer on medium-high speed, beat brown sugar, mascarpone, and butter in a large bowl until light and fluffy, about 4 minutes. Add eggs one at a time, beating to blend and scraping down the sides and bottom of bowl as needed.
Add flour mixture and mix on low until combined. Add bananas and mix together with a large spoon just until combined. Scrape batter into prepared pan; smooth top.
Bake bread until a knife inserted into the center comes out clean, 60–65 minutes. Transfer pan to a wire rack and let bread cool before slicing.
Recipe by Big City Tiny Kitchen at https://bigcitytinykitchen.com/classic-banana-bread/