1 ¼ cups (100g) unsweetened cocoa powder 
1 ¼ cups (150g) white whole wheat flour
1 ½ tsp baking powder
¾ tsp baking soda
¼ tsp salt
½ tbsp (7g) unsalted butter or coconut oil, melted and cooled slightly
2 large egg whites, room temperature
2 tsp vanilla extract
2 ½ tsp liquid stevia or powdered stevia
½ cup (120g) plain nonfat Greek yogurt
1 cup + 2 tbsp (270mL) nonfat milk, divided
¼ cup (56g) miniature chocolate chips, divided

Preheat the oven to 350°F, and coat 12 muffin cups with nonstick cooking spray. (If using liners, then line 12 muffins cups with liners and generously coat them with cooking spray.)

In a medium bowl, whisk together the cocoa powder, flour, baking powder, baking soda, and salt. In a separate bowl, whisk together the coconut oil or butter, egg whites, vanilla extract, and liquid stevia. Add in the Greek yogurt, stirring until no large lumps remain. Stir in ½ cup + 2 tablespoons of milk. Alternate between adding the flour mixture and remaining milk, beginning and ending with the flour mixture, and stirring just until incorporated. (For best results, add the flour mixture in 3 equal parts.) Set aside ½ tablespoon of miniature chocolate chips, and gently fold in the rest.

Divide the batter between the prepared muffin cups, and gently press the reserved miniature chocolate chips on top. Bake at 350°F for 21-24 minutes or until the tops feel firm to the touch and a toothpick inserted into the center comes out clean (or with a few crumbs attached). Cool in the pan for 5 minutes before transferring to a wire rack to cool completely.