Step 1

Prep: Preheat the oven to 425 F (220 C). Line a muffin tin with muffin liners or spray with nonstick spray.

Step 2

Mix Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, salt, and cinnamon if using.

Step 3

Mix the Wet Ingredients: In a separate bowl, whisk together the egg, milk, vanilla, oil, and sourdough discard until well combined.

Step 4

Combine Wet & Dry Ingredients: Pour the wet ingredients into the dry ingredients and stir with a spoon or rubber spatula until just combined. The batter will be lumpy. Do not over-mix or the muffins will become tough. If using, fold in any add-ins.

Step 5

Divide the batter evenly between the 10 muffin cups.

Step 6

Bake at 425 F for about 10 minutes and then turn the oven heat down to 350 F (175 C) for about 5-7 more minutes or until a toothpick inserted in the center comes out with moist crumbs.