Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Combine butter and sugars: In a large bowl, mix melted butter, brown sugar, and granulated sugar until smooth.
Mix the dry ingredients: In a medium bowl, whisk together flour, baking soda, baking powder, and salt.
Add egg yolk, Greek yogurt, and vanilla to the sugar mixture and stir until fully incorporated.
Fold in dry ingredients gently, then fold in chocolate chips. Avoid overmixing.
Scoop and flatten dough: Using a cookie scoop, scoop dough onto the baking sheet and gently flatten each cookie slightly to ensure even baking.
Bake 9-11 minutes until edges are lightly golden but the centers remain soft.
Notes
Use Full-Fat Yogurt: Low-fat or non-fat yogurt can result in a drier cookie.Chill the Dough: For slightly thicker cookies, chill the dough for 15–30 minutes before baking.Don’t Overbake: Cookies will look soft in the center when done. They firm up as they cool.Try Date Sugar: If you want a richer, caramel-like sweetness, swap a portion of your sugar for date sugar.