In a large bowl, whisk together the gluten-free flour, cocoa powder, baking powder, and salt. Add the eggs, milk, and melted butter. Mix until a thick batter forms. Stir in chocolate chips.
Optional: Chill the batter for 30 minutes. This gives the muffin a more tender texture.
Gluten-free Flour: This recipe was tested with Bob's Red Mill 1:1 Gluten-Free Baking Flour. Using a different flour might change the texture.