01 -
Preheat your oven to 425°F (220°C) and butter or line a 12-cavity muffin tin.
02 -
In a medium bowl, whisk together the flour, baking soda, baking powder, and salt.
03 -
Beat the butter and sugar together until light and fluffy, about 2 minutes. Add the eggs and vanilla, and continue mixing until combined.
04 -
Turn off your mixer, scrape down the sides, and fold in the sour cream and buttermilk.
05 -
Carefully fold in the flour mixture until almost combined, then stir in the chocolate chips.
06 -
Fill your muffin tins to the very top, about a generous 1/3 cup each. Optionally sprinkle with extra chocolate chips and coarse sugar.
07 -
Bake at 425°F (220°C) for 5 minutes. Turn down the oven to 375°F (190°C) and continue baking for 13-15 minutes.
08 -
Allow the muffins to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.