Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Using a mixer, combine butter and sugars (brown & white) in a large bowl until well incorporated.
Add the tahini, and the egg + egg yolk. Mix well.
In a separate smaller bowl, mix the flour, baking soda and salt with a fork or whisk.
Add half of the flour mixture to your wet ingredients, and mix on low until just incorporated. Then add your vanilla extract, and the remaining flour mixture.
Mix everything until just combined - don’t over-mix!
Fold in your chocolate chips.
Roll into 1.5 inch balls, and slightly flatten and shape your cookies on the baking sheet. Sprinkle with course sea salt.
Bake in the preheated oven for 8-12 minutes, or until edges are slightly brown.
Remove to a cooling rack and let sit for 10 minutes before enjoying.