Preheat the oven to 375°F (190°C) and prepare a 12-cup muffin tin with liners or non-stick spray.
In a medium bowl, combine the rolled oats and milk, and let sit for 10 minutes to soften the oats.
In a large bowl, whisk the eggs, melted butter, vanilla extract, brown sugar, and granulated sugar until smooth and slightly frothy.
Stir in the soaked oats (with the milk) into the wet mixture.
In a separate bowl, sift the flour, baking powder, baking soda, salt, and ground cinnamon. Gradually add these dry ingredients to the wet ingredients, stirring gently until just combined.
Carefully fold in the blueberries until evenly distributed.
Spoon the batter into the muffin tin, filling each cup about 3/4 full.
Bake for 18 to 20 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Allow the muffins to cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely.
Nutrition (Estimated per Serving):
Calories: 175
Carbohydrates: 27g
Protein: 4g
Fat: 6g