In a medium bowl whisk together all-purpose flour, vanilla whey protein powder, cocoa powder, baking powder, baking soda, and sea salt until evenly combined and free of lumps.

Wet ingredients

In a large mixing bowl, cream the softened unsalted butter with granulated sugar and light brown sugar using an electric mixer on medium speed until light and fluffy, about 2–3 minutes.

Add the egg and vanilla extract to the creamed mixture and beat until incorporated, about 30 seconds.

Mix in the plain Greek yogurt until smooth. Scrape down the bowl as needed to ensure even texture.

With the mixer on low speed, gradually add the dry ingredient mixture to the wet ingredients in two additions, mixing just until combined. Do not overmix. The dough should be slightly thick and hold shape; if it seems too dry, add 1–2 tablespoons milk.

Cookies & Cream mix-ins

Fold in the coarsely chopped chocolate sandwich cookies and white chocolate chips with a spatula until evenly distributed. Reserve a small handful (about 1–2 tablespoons) of chopped cookies for topping, if desired.

Using a 1.5 tablespoon cookie scoop or two spoons, portion dough into mounds about 1.5 inches apart on the prepared baking sheet. Gently press down the tops to flatten slightly and sprinkle reserved chopped cookie pieces on top of each mound. Optionally sprinkle a tiny pinch of flaky sea salt on each cookie.

Bake in the preheated oven for 10–12 minutes, rotating the sheet halfway through, until edges are set and centers look slightly soft. Cookies will continue to firm as they cool.

Remove from oven and let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.