
Preheat oven to 375F (190C) and line 15 wells of a 24-count mini muffin tin with paper liners (see note), alternating wells. Set aside.
In a large mixing bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
In a separate, medium-sized mixing bowl or a large measuring cup, whisk together sour cream, butter, egg, and vanilla until mixture is well-combined (it’s OK if the butter separates a bit, just do your best).
Add the wet ingredients into the dry ingredients and gently stir the ingredients together with a spatula. The batter will be quite stiff/dry, this is normal! When ingredients are about 50% combined, add in the chocolate chips and finish stirring until ingredients are just combined and no flour streaks remain.
Scoop batter by 1 ½ Tablespoon sized scoop into prepared muffin tin.
Bake in center rack of 375F (190C) preheated oven for 12-13 minutes. When muffins are finished baking you may notice some light golden browning and a toothpick inserted in the center should come out clean or with a few moist crumbs.
Allow muffins to cool in their pan for 5 minutes before carefully removing and baking your second batch of muffins.