Preheat your oven to 325°F and line a baking sheet with parchment paper. In a medium bowl, whisk together almond flour, powdered erythritol, and salt.
In a separate large bowl, beat the egg whites with cream of tartar using a hand mixer on high speed until stiff peaks form, about 2-3 minutes.
Add the almond extract to the whipped egg whites and gently fold in the almond flour mixture in two additions, using a spatula with slow, sweeping motions to avoid deflating the whites.
Keep folding patiently until the mixture comes together into a soft, slightly sticky dough that holds its shape when scooped. Do not overmix or the cookies will turn out flat. Scoop rounded tablespoons of dough onto the prepared baking sheet, spacing them about 1 1/2 inches apart. Gently press a few sliced almonds into the top of each cookie.
Bake for 16-18 minutes until the cookies are golden on the outside with beautiful cracks across the top.
Let the cookies cool completely on the baking sheet before removing. They will develop their signature crisp, crackled exterior and soft, chewy almond interior as they cool. Store in an airtight container at room temperature.
