Preheat oven to 375°F (190°C). Line a muffin tin with paper liners or lightly grease it with butter or oil.

In a large bowl, whisk together flour, baking powder, baking soda, salt, and nutmeg. This ensures even rise and light texture.

In another bowl, whisk melted butter, granulated sugar, and brown sugar until smooth and creamy.

Add the Liquid Components:

Mix in eggs, buttermilk, sourdough discard, sour cream, and vanilla until smooth.

Gradually fold dry ingredients into the wet mixture until just combined. Don’t overmix, stop when you no longer see dry flour.

Gently fold in the chocolate chips, reserving a few to sprinkle on top. Coating them lightly in flour helps prevent sinking.

Spoon batter into muffin liners, filling each ¾ full. Top with extra chocolate chips for that bakery-style finish.

Let the batter rest for 10 minutes before baking. This allows the flour to hydrate and improves texture.

Bake for 18–22 minutes, or until a toothpick inserted in the center comes out clean. If the tops brown too quickly, tent with foil.

Cool in pan for 5 minutes, then transfer to a wire rack to finish cooling.

Store cooled muffins in an airtight container at room temperature for 3 days, in the fridge for 1 week, or freeze up to 3 months.