Preheat your oven to 375°F (190°C) and line a muffin tin with muffin liners or grease it lightly.

In a large mixing bowl, combine the all-purpose flour, granulated sugar, baking powder, salt, and baking soda. Whisk until well blended.

In another bowl, whisk together the egg, milk, melted butter, and vanilla extract until thoroughly mixed.

Pour the wet ingredients into the dry ingredients and gently stir using a rubber spatula or wooden spoon until just combined. Be careful not to overmix.

Fold in the blueberries gently to avoid breaking them apart.

Divide the batter evenly among the 12 muffin cups, filling each cup about ⅔ full.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted in the center of a muffin comes out clean.

Remove from the oven and let the muffins cool in the pan for 5 minutes. Then transfer them to a cooling rack to cool completely.

If using frozen blueberries, do not thaw them before adding them to the batter.

For an extra touch, sprinkle a little sugar on top of the muffins before baking for a sweet crust.

Muffins can be stored in an airtight container at room temperature for up to 3 days, or frozen for up to 3 months.