Preheat your oven to 350° F.

Using a stand or hand held mixer at medium high speed, cream together the butter, tahini, brown sugar, and white sugar until light and fluffy – about 3 minutes.

Add the egg, egg yolk, and vanilla and mix until thoroughly combined.

Add the flour, salt, baking soda, and baking powder. Use a fork to mix the dry ingredients a bit before you incorporate them into the wet. Then mix slowly until mostly mixed (there will still be some dry flour). Then add the chocolate chips and mix just until the dry flour disappears and the chocolate is dispersed into the batter.

Scoop ping pong sized balls onto a baking sheet with about an inch of room between each cookie (I fit about 14 per pan).

Bake for 9 minutes, rotating the pan halfway through baking.

Immediately after taking the cookies out of the oven, firmly (but carefully) drop the cookie sheet onto the counter from about 6 inches up. You will immediately see the cookies begin to flatten. Das good.

Sprinkle cookies with coarse salt.

Let the cookies cool on the pan for 2-3 minutes before transferring to a wire rack to cool completely.

Repeat with remaining dough.