Preheat the oven: Set to 350°F (175°C). Line a baking sheet with parchment paper.

Mix dry ingredients: In a bowl, whisk 1 1/2 cups almond flour, 1/2 cup protein powder, 1/3–1/2 cup sweetener (adjust to taste), 1 teaspoon baking powder, and 1/4 teaspoon salt. Break up any almond flour clumps for even texture.

Cream the fat and sweetener: In a separate bowl, beat 6 tablespoons softened butter with the sweetener (if you prefer a finer crumb, cream half the sweetener here and keep half in the dry mix). Mix until light and slightly fluffy, about 1–2 minutes.

Add wet ingredients: Beat in 1 egg and 1 teaspoon vanilla extract. Stir in 1 teaspoon lemon zest if using.

Combine: Add the dry ingredients to the wet. Stir until a soft dough forms. If it’s too dry or crumbly, add 1–2 tablespoons unsweetened almond milk to bring it together. The dough should be thick, not sticky.

Fold in blueberries: Gently fold in 1/2 cup blueberries. If using frozen, do not thaw—toss them with a teaspoon of almond flour first to reduce bleeding.

Scoop: Use a tablespoon or small scoop to portion 12–14 mounds onto the baking sheet. Lightly press each mound to about 1/2-inch thick; they won’t spread much.

Bake: Bake for 10–13 minutes, until edges are set and lightly golden. Centers should still look a touch soft.

Cool: Let cookies cool on the sheet for 10 minutes, then transfer to a rack. They firm up as they cool.

Optional glaze: For a bright finish, mix 2 teaspoons lemon juice with powdered erythritol to drizzle. Keep it light to stay keto-friendly.