Add Erythritol, sugar, salt, flour, protein powder, cocoa powder, baking powder, baking soda, and xanthan gum to a large bowl and whisk together.
In a separate bowl, whisk together the egg, egg yolks, chocolate milk, Greek yogurt, and avocado oil.
Fold the wet ingredients into the dry ingredients until just combined.
Scoop the batter into a jumbo muffin pan lined with baking cups, filling each cup to 160 g.
Top each muffin with 6 pieces of chocolate chips.
Bake at 300°F for 38-42 minutes, until no longer jiggly.
Allow to cool before serving.
