01 - Preheat the oven to 375°F (190°C) and arrange an oven rack to the middle position.
02 - Line a standard 12-cup muffin tin with paper liners or lightly grease each cup with butter.
03 - In a large bowl, whisk together flour, oats, baking powder, baking soda, and salt until thoroughly blended.
04 - In a separate bowl, beat eggs with sugar until well combined. Stir in melted butter, milk, and vanilla extract.
05 - Pour wet ingredients into the dry mixture and gently fold until just combined. Do not overmix.
06 - Gently fold in blueberries, reserving a few for topping if desired.
07 - Evenly divide batter among muffin cups, filling each about three-quarters full.
08 - Bake for 20 to 25 minutes or until muffins are golden and a toothpick inserted in the center comes out clean.
09 - Transfer muffins to a wire rack to cool for at least 10 minutes before serving.