Gluten free, Grain Free Chocolate Brownie Cookies

3 cups gluten-free powdered sugar
3/4 cup unsweetened cocoa powder
1 teaspoon kosher salt
2 large egg whites
1 large egg
4 oz. bittersweet chocolate, chopped
3 Tablespoons cacao nibs

1.    Place racks in lower and upper thirds of oven; preheat to 350°. Whisk powdered sugar, cocoa powder, and salt in a large bowl, then whisk in egg whites and egg; fold in chocolate and cacao nibs. Spoon batter by the tablespoonful onto 2 parchment-lined baking sheets, spacing 2″ apart.

2.    Bake, rotating sheets once, until cookies are puffed, cracked, and set just around the edges, 14-16 minutes.

3.    Transfer baking sheets to wire racks and let cookies cool on pan (they’ll firm up).

4.    Cookies can be baked 3 days ahead. Store airtight at room temperature.