Using a hand or stand mixer cream the butter and coconut sugar.
Add the egg whites followed by the vanilla extract.
Turn off your mixer and use a spatula to mix in the almond flour until all ingredients are incorporated (the batter will be soft).
Spoon about ½ tablespoon of the batter for each cookie onto a baking sheet lined with parchment paper, spacing them 2 inches apart giving them room to spread while baking.
Bake at 350°F for 10 minutes or until light golden brown around the edges. Let cookies cool on the baking sheet over a wire rack.
Melt dark chocolate in a bowl over simmering water (double boiler) and drizzle on top of the cooled butter cookies.
Notes
Recipe makes 10 cookies. Store in an airtight container at room temperature or in the fridge.