Step 1: Prepare the Batter
Preheat oven to 350°F (175°C).
Line a muffin tin with paper liners or grease it well.
In a large bowl, stir together oats, baking powder, cinnamon, and salt.
In another bowl, whisk eggs, milk, maple syrup or honey, applesauce, and vanilla.
Pour wet ingredients into dry and stir to combine.
Fold in your favorite mix-ins.
Step 2: Fill the Muffin Tin
Spoon the batter evenly into 12 muffin cups, filling each nearly to the top.
Step 3: Bake
Bake for 25–30 minutes, or until tops are golden and set.
Cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.