01 -
Preheat oven to 425°F. Place muffin liners in every other cup of a muffin pan.
02 -
Melt butter, then mix with sugars in a large bowl. Add eggs one at a time, then mix in vanilla, buttermilk, and sourdough discard.
03 -
Add flour, baking powder, baking soda, and salt, mixing until just combined. Gently fold in chocolate chips.
04 -
Let batter rest for 20-30 minutes at room temperature.
05 -
Fill muffin cups to the top using a 1/4 cup measure. Bake at 425°F for 10 minutes, then reduce temperature to 350°F (without opening oven) and bake 10-13 minutes more until a toothpick comes out with moist crumbs.
06 -
Let muffins cool in the pan for 10 minutes before transferring to a wire rack. Serve warm with butter if desired.