Preheat the oven to 350 degrees. Prep a muffin tin with nonstick spray or muffin liners.
In a bowl, combine one egg, 4 tablespoons of cooled, melted butter, 120 grams of sourdough discard, ⅓ cup of milk, and ½ cup of brown sugar.
Next, add 1 cup of flour, 4 tablespoons of cocoa powder, ½ teaspoon of baking soda, and ¼ tsp of salt. Whisk together until incorporated, but don’t overmix.
Fold in the ½ cup of peanut butter chips.
Portion out the batter into 12 muffin tins. Fill each muffin cup about ⅔ full and bake at 350 degrees for 18 to 20 minutes or until a toothpick inserted into the middle comes out clean.
Let cool and serve! If the muffins are sticking to the liners or the muffin tin, let them cool more and try again.
