Preheat your oven to 400°F and grease or line your muffin tin with paper liners.
Combine 2 ½ cups all-purpose flour, 2 teaspoons baking powder, 1 teaspoon baking soda, and ½ teaspoon salt in a medium bowl. Set aside.
In a large bowl, mix the melted ½ cup unsalted butter, ¾ cup granulated sugar, and ½ cup brown sugar. Add the 2 large eggs, 1 cup whole milk, and 2 teaspoons vanilla extract. Whisk until well combined.
Fold the dry ingredients into the wet ingredients until just combined. Gently fold in 2 cups fresh blueberries.
Fill the prepared muffin cups most of the way full, then bake in the preheated oven for 5 minutes.
After 5 minutes, turn the oven temperature down to 350°F and continue baking for 14-17 minutes more. A toothpick in the center should come out clean.
When the muffins are done, remove from the oven, cool, and serve!
Notes
If you don’t melt the butter completely, the muffins may not rise properly. So make sure the butter is completely melted before mixing it with the sugars to avoid flat muffins!
These keep well in an airtight container for up to 3 days or up to 3 months in the freezer. Store them with a paper towel on top to keep them fresher, for longer!