Preheat the oven to 350°F and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the almond flour and 3/4 cup powdered low carb sweetener until no lumps remain.

Add the egg whites, lemon zest, lemon juice, and yellow food coloring if using, then stir with a rubber spatula until a thick, sticky dough forms.

Let the dough rest for 2 to 3 minutes so the almond flour can absorb some moisture and become easier to roll.

Place the 1/4 cup powdered sweetener for rolling into a shallow bowl.

Using a small cookie scoop or tablespoon, portion the dough into equal mounds, then roll each portion between your palms to form smooth balls.

Roll each dough ball in the powdered sweetener to coat lightly, then place on the prepared baking sheet, spacing them about 2 inches apart.

Gently press each ball with the bottom of a flat glass or spatula to flatten to about 1/2 inch thick.

Bake on the center rack for 12 to 15 minutes, until the edges are lightly golden and the tops look set and matte.

Remove the baking sheet from the oven and let the cookies cool completely on the pan before handling, then transfer to an airtight container for storage.