Tahini gives ordinary cookie dough rich, toasted sesame flavor. It has a subtle presence in the baked cookie that makes you pause to admire that little something-something different after each bite.
Preheat oven to 325°F. Line two large baking sheets with parchment paper.
Place the butter, tahini, and sugars in the bowl of an electric mixer. Beat at medium-high speed until well incorporated. Add the egg and vanilla. Beat again until combined.
In a separate bowl, whisk together the flour, baking soda, baking powder and salt. Add the flour mixture to the butter mixture and beat on medium speed until combined. Add the chocolate chips and beat on low speed until the chips are well dispersed into the cookie dough.
Scoop dough into heaping tablespoons and place them at least 2-inches apart on the prepared pans. Bake for 15 minutes. The baked cookies will be pale on top and golden on the bottom. Let them stand on the baking sheet for 5 minutes, or until they are firm enough to transfer to a wire rack for cooling.
Cookies will keep well in an air-tight container or tightly covered in plastic wrap.