Black Sesame Banana Cake with Peanut Butter

Directions

1. Preheat oven to 350° F. Butter one 9 x 5 x 3-inch loaf pan. Whisk the flours, baking powder, baking soda, salt, and two tablespoons of the black sesame seeds in a medium bowl. Grind the remaining sesame seeds in a spice mill to form a thick paste, about 2 minutes. Set aside.
2. Using an electric mixer or a stand mixer fitted with a paddle attachment, cream the butter and sugar until well-combined, 2 to 3 minutes. Add the sesame paste and beat, occasionally scraping down the sides, until blended, 1 to 2 minutes. Add the egg and egg yolk and beat until pale and fluffy, 3 to 4 minutes. Beat in the mashed banana.
3. On low speed, beat in flour mixture in 3 additions, alternating with the buttermilk in 2 additions. (Begin and end with the dry ingredients.)
4. Spoon the batter into the prepared pan. Dollop peanut butter over top and use a knife to swirl it into the batter. Smooth the top, then sprinkle sesame seeds and granulated sugar over top. Bake for 45 minutes to 1 hour, until a tester comes out with only a few moist crumbs.
5. Cool completely in the pan before turning out and slicing.