Step 1

Sift together the flour and baking soda. Set aside.

Step 2

Place the butter, sugar, brown sugar, and salt in the bowl of a stand mixer fitted with the paddle attachment. Beat at medium speed for about 1 minute, just until it lightens slightly.

Step 3

Add the egg, tahini, milk, and vanilla, and beat at medium speed until smooth (just about 30 seconds). Scrape down the sides halfway through to make sure it fully incorporates.

Step 4

Add the dry ingredients to the wet ingredients, and stir together at low speed until it comes together. Don’t overmix it, and stop as soon as there are no dry patches.

Step 5

Cover and chill the cookie dough in the refrigerator for at least 1 hour, up to 24.

Step 6

Once the cookie dough is ready, preheat the oven to 375°F (190°C) convection**, and shape it into about 3 dozen small balls (about 20g each, with a #50 cookie scoop, or 1 slightly heaping tablespoon). Roll them generously in sesame seeds, and place a couple inches apart on parchment-lined cookie sheets.

Step 7

Bake for about 8 minutes, just until they’re puffy and light brown. Remove from the oven, place a kiss in the center of each (push them down slightly so they’re a little embedded in the dough), and return to the oven for 2 minutes, until the cookies are golden brown.

Step 8

Let them cool on the cookie sheet for 1 minute, then slide the parchment off the sheet pan to cool the rest of the way. The chocolate will harden slightly at room temperature, until it’s a little softer and gooier than before, but set. Feel free to chill them in the fridge to hurry the cooling along.