To make the brown butter, melt butter in a clear heavy bottom pot. Once the butter starts to foam, whisk continuously until brown bits start to form. Remove from heat, pour into clean bowl, skim the foam from the top and cool to room temperature (25 minutes). The butter should begin to solidify slightly.
In a separate bowl, whisk together flour, baking soda and powder and salt. Set aside. In a mixing bowl, with paddle attachment, cream together the browned butter, sugar and tahini until light and fluffy (3-4 minutes). Add in orange zest and combine until fully incorporated. Add in eggs and yolk one at a time, beating until each is well incorporated. Add orange and vanilla vanilla extract, beat until combined. Add orange juice and and beat until well incorporated (about 1 minute).
Add dry ingredients to the wet 1/3 at a time. Mix on lowest setting until JUST combined. I like to leave about 10% flour mixture visible before adding more. Scrape down sides of mixing bowl before adding the next 1/3. Do not overmix. Gently fold in chocolate chips, chunks or disks. Scoop out dough using a 2" cookie scoop with trigger release onto aparchment lined baking sheet. Dough balls can be close together as you will not be baking these. Wrap sheet pan in plastic wrap and chill in the freezer for minimum 4 hours to overnight.
Line a large baking sheet with parchment paper. Preheat oven to either 325F or 350F. (see notes for differences). Bake at for 12-18 minutes or until cookies are set around the edges. The center may still look slightly underbaked. Pull cookies from the oven, cool on the cookie sheet placed on top of a cooling rack for 3-4 minutes. Using a spatula, gently removed cookies from the pan, onto a cooling rack and cool an addiotnal 10-15 minutes.