01 - Preheat the oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease the cups.
02 - In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until evenly mixed.
03 - In a separate bowl, beat the eggs, then whisk in the milk, vegetable oil or melted butter, and vanilla extract until fully blended.
04 - Pour the wet mixture into the dry ingredients and stir gently until just combined, avoiding overmixing to maintain tenderness.
05 - Carefully fold in the blueberries to distribute them without breaking or bruising.
06 - Spoon batter evenly into the muffin tin, filling each cup about three-quarters full. Sprinkle with coarse sugar if desired.
07 - Bake for 18 to 22 minutes until a toothpick inserted in the center comes out clean.
08 - Allow muffins to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.