Preheat oven to 350 degrees. Line 18 muffin tins with paper liners and set aside.
In a large bowl, whisk sugar, flour, oat bran, cinnamon, soda, and salt together until well combined. Create a well in the center of the dry ingredients and add remaining wet ingredients: pumpkin, maple syrup, eggs, oil, vanilla, and milk.
Slowly whisk all ingredients together until smooth batter forms.
Scoop into muffin tins 2/3 full and sprinkle with rolled oats. Bake 15-20 minutes or until toothpick comes out clean.
Serve warm with butter or cool to room temperature and store in airtight containers for up to three days on the counter or up to 5 days in the fridge.