Sift sugar, flour, cocoa powder, baking powder, baking soda, and salt into a large bowl.
Add the egg, oil, sour cream, and vanilla to a separate bowl and whisk together.
Pour the wet mixture into the dry with half of the chocolate chips, and use a spatula or wooden spoon to mix until combined. Do not over mix.
Add the remaining chocolate chipes and lightly mix.
Scoop into prepared muffin tin.
Bake for 14-17 minutes or until a toothpick comes out clean.
Allow the muffins to cool in the pan for about 5-10 minutes after removing them from the oven.
Use a butter knife or offset spatula to gently loosen the edges of each muffin from the pan.
Carefully transfer the muffins from the pan to a wire cooling rack.
Serve and enjoy!
Notes
Use a cookie scoop to measure out the same amount of batter for each muffin. This ensures that all the muffins bake evenly and have a uniform size...plus it helps prevent spills and keeps the muffin batter from dripping and sticking to the pan.
Use full fat ingredients for the best flavor and texture.