Line two muffin pans with 18 paper liners.

In a medium sized mixing bowl, whisk together the flour, baking powder, salt, and baking soda.

In a large mixing bowl, stir together the granulated sugar, sour cream, sourdough discard, melted butter, eggs, milk, and vanilla extract.

Add in the dry ingredients and then gently stir until barely combined.

Stir in the chocolate chips until just mixed in.

Divide the batter equally into a prepared muffin pans.

Sprinkle the tops with course sugar.

Bake in a preheated oven for 18-25 minutes, until the tops of the muffins are golden brown and a toothpick inserted into the center comes out mostly clean.

Allow the muffins to cool for at least 5 or 10 minutes before enjoying.