1/2 cup (1 stick) unsalted butter, softened to room temperature
1 1/3 cups sugar, plus additional for topping the cake
Sift together the flour, almond meal, baking powder, baking soda, and salt, and stir in 2 tablespoons of sesame seeds. Set aside.
Take the remaining 1/2 cup black sesame seeds, and grind them until they form a thick paste (this is easiest in a spice grinder, but with enough patience and scraping, you can use a blender). Set aside.
Cream the butter and sugar together until fluffy and well combined, scraping down the sides occasionally. Add the sesame paste, and beat another minute, then add the egg and yolk, and beat until pale and fluffy (3-4 minutes).
Fold in 1/3 of the flour mixture until just barely combined, then 1/2 the buttermilk. Repeat, ending with the flour, then fold in the pear. Pour into the loaf pan, smooth the top, and sprinkle with a few spoonfuls of sugar. Bake until a tester comes out clean, 50 minutes to 1 1/2 hours (yeah, I know that's a crazy big range, but the reports seem to back it up — mine definitely took the full hour and a half). Let cool in the pan, then turn out, slice, and enjoy.