Preheat and prep: Heat your oven to 350°F (175°C). Line a baking sheet with parchment paper for easy removal.

Cream the butter and sweetener: In a mixing bowl, beat 1/2 cup softened butter with 2/3 cup granulated keto sweetener until fluffy, about 1–2 minutes. This helps create a tender crumb.

Add wet ingredients: Mix in 1 large egg and 1 teaspoon vanilla extract until smooth and well combined.

Combine dry ingredients: In a separate bowl, whisk 2 cups super-fine almond flour, 1 tablespoon coconut flour, 1 teaspoon cream of tartar, 1/2 teaspoon baking soda, and 1/4 teaspoon fine sea salt.

Bring the dough together: Add the dry mixture to the wet ingredients and stir until a soft dough forms. If using brown-style keto sweetener for deeper flavor, fold in 1–2 tablespoons now.

Chill briefly (optional but helpful): If the dough feels sticky or warm, chill for 15–20 minutes. This makes rolling easier and helps cookies hold their shape.

Mix the coating: In a small bowl, stir 3 tablespoons granulated keto sweetener with 1–1.5 teaspoons ground cinnamon. Adjust to taste.

Portion and roll: Scoop about 1.5 tablespoons of dough per cookie. Roll into balls with your hands, then roll each ball in the cinnamon-sweetener mixture to coat.

Flatten slightly: Place coated dough balls on the lined baking sheet, spaced about 2 inches apart. Gently press to flatten to roughly 1/2 inch thick for a classic snickerdoodle look.

Bake: Bake for 9–11 minutes, until the edges are set and the tops look slightly puffy. The centers should still look a bit soft; they’ll firm as they cool.

Cool: Let the cookies cool on the baking sheet for 10 minutes, then move to a wire rack. Keto cookies are delicate when hot and need that rest time.

Finish: If you like extra coating, dust with a pinch more cinnamon-sweetener while warm.