Ingredients 2 cups (9oz 255g) all purpose flour، lightly spooned and leveled 2 teaspoons baking powder ½ teaspoon baking soda ¼ teaspoon salt ¾ cup (6oz 170g) unsalted butter، softened to room temperature 1 cup (7 oz 200g) sugar 2 eggs، at room temperature 2 teaspoons pure vanilla extract، (4 teaspoons if using imitation vanilla) 1 cup (8oz 227g) sour cream، at room temperature 1 cup (6 oz 170g) semi-sweet (or milk or bittersweet) chocolate chips، preferably minis (see note for substitution)، plus extra for sprinkling over the top
Directions Adjust the oven rack to the lower middle position and preheat the oven to 400F200C. Line a 12 cup muffin pan with 12 cupcake liners (or 48 mini liners، if using mini cupcake pan). In a medium bowl، whisk together the flour، baking powder، baking soda and salt. Set aside. In the bowl of a stand mixer fitted with a paddle attachment (or a handheld mixer and a large bowl) beat the butter on medium high speed until creamy and lightened up; 1 to 2 minutes. Add the sugar and beat together until lightened up in both color and texture; 4 to 5 minutes. The color should turn very pale and texture should look fluffy. Add the eggs، one at a time، beating well after each addition. Add in the vanilla and beat together for one minute. On lowest speed، add in one-third of the flour mixture and mix until mostly combined. Add in half of the sour cream and lightly stir until almost mixed in. Continue with adding another one-third of the flour mixture، followed by the remaining sour cream and ending with the last third of flour mixture. Mix until just combined. DO NOT OVERMIX or you could end up with tough muffins. Using a rubber spatula، fold in the mini chocolate chips (see note for regular sized). Using an ice cream scoop، divide the batter evenly among the prepared muffin pan، filling the cups almost to the top; about ½ cup of batter for regular muffins and 2 tablespoons for the minis. Sprinkle the tops with some extra chocolate chips Bake for 15 to 18 minutes (for regular muffins)، or until the top are golden brown and spring back to the touch and a toothpick inserted in center comes out clean or with a few moist crumbs attached. Mini muffins should bake in about 9 to 12 minutes. (Always check early for doneness and add a few minutes if still not baked through). DO NOT OVERBAKE or the muffins will dry out. Allow muffins to cool in the pan for about 5 minutes، then transfer to a wire rack and allow to cool slightly before serving. Served warm or at room temperature. Allow to cool completely before storing. Store leftovers in an airtight container to retain its moisture.
Notes I love using MINI chocolate chips here because unlike the regulars، they don't sink to the bottom of the muffins and for their even distribution in the batter، so you get a pop of chocolate with every bite. Regular chocolate chips or chopped chocolate could be used instead. However، be sure to reserve a tablespoon of the flour mixture aside and use it to coat the chips or chunks before folding into the batter. This will help prevent them from sinking.