1/2 cup unsalted butter, melted and slightly cooled
1/2 cup honey
1 large egg, at room temperature
1 teaspoon pure vanilla extract
Sugar for sprinkling on top
Combine milk and oats and set aside in the fridge to soak up the moisture.
Spray a 12-count muffin pan with nonstick spray and preheat oven to 425°F.
Combine the flour, baking powder, baking soda, cinnamon, and salt together in a large bow. Set aside. Whisk the melted butter, honey, egg, and vanilla extract together in a medium bowl until combined. Pour the wet ingredients into the dry ingredients, stir a few times, then add the soaked oats and blueberries. Fold everything together gently just until combined.
Fill the container all the way to the top with the batter. Top with oats and a light sprinkle of sugar. Bake for 5 minutes at 425 then, keeping the muffins in the oven, reduce the oven temperature to 350°F. Bake for an additional 16-17 minutes or until a toothpick inserted in the center comes out clean. The total time these muffins take in the oven is about 22-23 minutes. Allow the muffins to cool until room temperature.