Preheat oven to 350 degrees Fahrenheit. Line an 8x8 baking pan with parchment paper (or grease well) and set aside.
In a bowl, add butter, granulated sugar, brown sugar, vanilla, and eggs. Stir until fully combined.
In a separate bowl, sift together dry ingredients - cocoa, flour, and salt. Slowly stir dry ingredients into wet ingredients until combined.
Add tahini and chocolate chips and stir until incorporated. Pour batter into prepared pan and spread into an even layer - batter will be thick.
Top with sesame seeds and optionally a few more chocolate chips. Bake for 20-24 minutes or until a toothpick inserted into the center comes out with crumbs (not raw batter).
Place brownies onto a wire rack and allow to cool completely before cutting and enjoying.
Brownies can be made ahead and stored, uncut, in a sealed container for 1-2 days before slicing and serving. Brownies can be frozen as a whole slab or individual servings in a freezer safe container for up to 3 months. Thaw frozen brownies on the counter top at room temperature. Tahini can be substituted with your favorite nut or seed butter for a different flavor.