Preheat oven to 425°F.
Spray a 12-count muffin pan with non-stick spray or use cupcake liners.
In a large bowl, whisk the flour, sugar, cocoa powder, baking soda, salt, and chocolate chips together. Set aside.
In another bowl, whisk the eggs, sour cream, oil, milk, and vanilla extract together until combined.
Pour wet ingredients into dry ingredients and fold together with a silicone spatula.
Spoon the batter into liners or greased muffin pan.
Bake for 5 minutes at 425°F, then reduce the oven temperature to 350°F. Bake for an additional 15-16 minutes or until a toothpick inserted in the center comes out clean.
Cool muffins for 10 minutes in the pan, then transfer to a wire rack until fully cooled. Enjoy!