Preheat oven to 350 degrees Fahrenheit. In a medium-sized mixing bowl or stand mixer, combine milk, butter, maple syrup, eggs, and sourdough discard.
Add in flour, baking powder, yellow cornmeal, and salt. Mix until well combined.
Use the method of your choice to scoop the batter into a prepared muffin tin (I recommend a small cookie scoop). You can grease, butter, or even line the muffin tin with cupcake liners if you would prefer an easier cleanup. Fill each muffin compartment close to the top but not all the way.
For mini muffins, bake for 10-12 minutes. It is usually closer to 10 minutes for me; you will know they are done when you can lightly tap the top of the muffins and they feel soft but firm. For standard-sized muffins, bake for 25-30 minutes.
Allow to cool for 5 minutes in the pan before removing. If you grease your pan, you might need to use a knife to loosen the edges a bit. Enjoy!
