Preheat oven to 350°F. Coat a 9- x 5-inch loaf pan with cooking spray.

Combine banana, buttermilk, tahini, melted butter, vanilla extract, and eggs in a large bowl. Beat with an electric mixer at medium speed until combined. Add sugars and beat just until combined.

In a separate bowl, combine flour, baking soda, and salt in a bowl. Add flour mixture to banana mixture and mix just until combined. Fold in chocolate chunks. Pour batter into prepared pan and sprinkle with mini chocolate chips and toasted sesame seeds.

Bake at 350°F for 55 minutes or until a wooden pick inserted in the center comes out clean. Cool in pan 10 minutes on a wire rack. Remove bread from pan and cool completely before slicing.