Place racks in upper and lower thirds of oven and preheat to 350°. Whisk flour, baking powder, and salt in a medium bowl. Using an electric mixer on medium speed, beat butter, sugar, and honey in a large bowl until light and fluffy, about 3 minutes. Beat in tahini, then add dry ingredients in 2 batches, beating after each addition until fully combined. Dough will be slightly sticky.

Place sesame seeds in a small bowl. Scoop out heaping tablespoons of dough (about 1 oz.) and roll into balls. Dip tops of balls in sesame seeds, pressing to adhere, and place, sesame side up, on 2 parchment-lined baking sheets, spacing about 2″ apart. Bake cookies, rotating baking sheets halfway through, until golden brown, 13–15 minutes. Let cool on baking sheets (cookies will firm as they cool).