Preheat the oven to 425°F. Line a 12-cup muffin pan with paper liners or grease the cups well.
In a large bowl, combine the quick oats, milk, and vinegar. Let the mixture sit for 3 minutes so the oats can absorb some of the liquid.
1 cup Quick Oats, ½ cup 2% Milk, 1 Tbsp White Vinegar
Add the vegetable oil, white sugar, egg, and vanilla extract. Stir until combined.
½ cup Vegetable Oil, ½ cup White Sugar, 1 Lrg Egg, 1 Tsp Vanilla Extract
Add the flour, salt, baking soda, and baking powder. Stir just until no dry streaks remain.
1 cup All-purpose Flour, 1 Tsp Salt, ½ Tsp Baking Soda, 1 Tsp Baking Powder
Place the frozen blueberries in a small bowl and toss them with 1 tablespoon flour. Fold the blueberries gently into the muffin batter.
1 Tbsp All-purpose Flour, 1 cup Blueberries
Divide the batter evenly among the 12 muffin cups.
Sprinkle the tops with coarse crystal sugar.
2 Tbsp Coarse Sugar Crystals
Bake at 425°F for 10 minutes.
Without opening the oven, reduce the temperature to 350°F and continue baking for 15 minutes, or until a toothpick inserted in the center comes out clean.
Cool in the muffin pan for 5 minutes before transferring the muffins to a wire rack to cool completely.