Prep your tools: Line a baking sheet with parchment paper. Set your oven to 325°F (163°C), but don’t preheat yet if you plan to chill the dough first.

Cream the butter and sweetener: In a medium bowl, beat softened butter with powdered sweetener until light and fluffy, about 1–2 minutes.

Add flavor: Mix in lemon zest, lemon juice, vanilla, and salt. The mixture may look slightly curdled from the juice—don’t worry.

Bring in the dry ingredients: Add almond flour. If using, add 1/2 teaspoon xanthan gum and 1 tablespoon coconut flour. Stir until a soft dough forms that holds together when pressed.

Chill the dough: Shape into a log about 1.5 inches in diameter, wrap in parchment or plastic, and chill for 30–45 minutes. This helps the cookies slice cleanly and bake evenly.

Slice and arrange: Preheat the oven to 325°F (163°C). Unwrap the dough and slice into 1/4-inch rounds. Place on the lined baking sheet with a little space between each piece.

Bake: Bake 11–14 minutes, until the edges are just turning golden. The centers will look soft but set as they cool.

Cool completely: Let the cookies cool on the sheet for 10 minutes, then move to a rack. Keto cookies firm up as they cool—don’t rush this step.

Optional glaze: Whisk 1/2 cup powdered sweetener with 1–2 tablespoons lemon juice and a splash of cream or almond milk until smooth and pourable. Drizzle over fully cooled cookies and add a pinch of zest on top.