3 tablespoons unsalted butter, softened, divided use
1/2 cup granulated sugar
1/2 cup firmly packed light brown sugar
2 large eggs
1 1/2 teaspoons vanilla extract
1/2 cup milk
3/4 cup semi-sweet or dark chocolate chips
1 1/2 teaspoons turbinado sugar, optional
Preheat oven to 350 degrees F. Coat a 9-inch loaf pan with cooking spray or butter.
In a medium sized mixing bowl, sift together flour, baking powder, baking soda and salt.
In a large mixing bowl, using a mixer on medium speed, beat together banana, peanut butter, 2 tablespoons butter, granulated sugar and brown sugar until creamy, about 2 minutes; beat in eggs and vanilla extract until combined. Reduce mixer speed to low and beat in milk and flour mixture until just combined; stir in chocolate chips
Pour batter into prepared pan; bake for 50 minutes. Remove pan from oven, melt additional tablespoon butter, brush evenly over the top, and top with turbinado sugar. Continue to bake an additional 5 minutes or until golden brown.
Cool for 20 minutes before running a knife around outside edges, removing, and transferring to a wire rack to cool an additional 30 minutes before slicing.