4 large eggs, separated to whites
⅛ teaspoon cream of tartar
½ cup sugar
1 teaspoon vanilla extract
2 tablespoons unsweetened cocoa powder
1 cup mini chocolate chips
Heat oven to 300°F. Cover baking sheet with parchment paper or silicone baking mat.
Beat egg whites and cream of tartar until soft peaks form. Slowly add sugar, followed by vanilla and continue to beat until stiff peaks form. Sugar should be dissolved and egg whites glossy in appearance.
Sift cocoa powder into egg whites and fold gently until combined.
Fold in chocolate chips, then drop even-sized heaping scoops onto cookie sheet.
Bake 35-40 minutes or until cookies are just dry. Cool slightly before removing from cookie sheet. Transfer to wire rack to finish cooling. Store at room temperature in an airtight container.