Tahini Crisps

My baking friend and I made this for my son's wedding, and then took them on a work trip and the only recipe that I got asked for was this one. They are not too sweet, but buttery and nutty. ¼ cup firmly packed (54 grams) light brown sugar, preferably Muscovado 2 tablespoons (25 grams) granulated sugar 4 tablespoons (57 grams) unsalted butter (½ stick), softened ½ cup plus 1 tablespoon (143 grams) tahini, preferably Soom brand, at room temperature ½ lightly beaten large egg (25 grams) ¼ teaspoon (1.25 ml) pure vanilla extract ½ cup plus 1½ tablespoons (71 grams) bleached all-purpose flour ½ teaspoon (2.7 grams) baking soda A pinch of fine sea salt ¼ cup (42 grams) hulled sesame seeds, for coating Make the dough: In a food processor, process sugars for several minutes, until very fine. With the motor running, add butter one tablespoon at a time and process until smooth and creamy. Scrape down sides of bowl as needed. Add tahini and process until smooth and creamy. In a small bowl, whisk together beaten egg and vanilla extract. Add egg mixture to food processor and process until incorporated, scraping down sides of bowl as needed. In a small bowl, whisk together flour, baking soda and salt. Add flour mixture to food processor and pulse just until incorporated. Scrape dough into a bowl. Cover and refrigerate for a minimum of 1 hour and up to overnight, to firm for shaping. When ready to bake, set an oven rack in middle position. Set oven to 375 degrees. Roll the dough into balls: Place sesame seeds in a small bowl or ramekin. Measure out 10 pieces of dough, 1 level tablespoon (18 grams) each. Roll each piece of dough between the palms of your hands to form a 1-inch ball, then roll ball in sesame seeds to coat. Place balls 1½ inches apart on a cookie sheet. Bake for 6 minutes. Rotate cookie sheet a half turn. Continue baking until cookies lightly brown and centers, when lightly pressed, have barely any give, 6-9 minutes. Let cookies cool on cookie sheet until firm enough to lift, about 1 minute. Use a thin pancake turner to transfer cookies to a wire rack. Let cool completely.