Preheat oven to 425 degrees.
In one bowl combine 1 and ¼ cup rolled oats, 1 and ¼ cup flour, 1 Tbsp baking powder, 1 tsp ground cinnamon, and ⅓ cup sugar.
In another bowl, mash one ripe banana, 1 cup milk, ¼ cup vegetable oil, and 1 beaten egg.
Pour wet ingredients into dry ingredients along with ¾ cup frozen blueberries. Stir until just combined.
Add to greased muffin tins (preferably larger tins that make six muffins) and top with cinnamon and sugar.
Bake for 20 mins (or 15 mins if you are using a 12 muffin tin).
