Preheat the oven to 425ºF. Spray a 6-cup jumbo muffin pan or a 12-cup muffin pan with nonstick cooking spray or coat well with softened butter. Set aside
If using fresh blueberries, rinse them well then spread out on a paper towel lined baking sheet. Pick through the blueberries to ensure there are no stems and no rotten or moldy berries. Using a dry paper towel, gently press on the berries to remove excess moisture. Set aside while you prepare the batter. If using frozen blueberries, do not thaw. Separate any big clumps of frozen berries and set aside while you prepare the batter 2 cups blueberries
In a large mixing bowl, whisk together flour, baking powder, and salt. Set aside.
2 ½ cups all-purpose flour, 1 tablespoon baking powder, 1 teaspoon kosher salt
In a separate mixing bowl, whisk together the vegetable oil, brown sugar, eggs, milk, sour cream, and vanilla until well incorporated and smooth.
⅓ cup vegetable oil, 1 cup brown sugar , 2 large eggs , 2 teaspoons vanilla extract, ½ cup whole milk, ½ cup full-fat sour cream
Gently fold in the dry ingredient mixture until no dry spots of flour are left. Set aside
If using fresh blueberries: In a small bowl, add ½ cup of the blueberries. Using a fork, crush the berries. In a separate small bowl, add the remaining 1 ½ cups of blueberries, ensuring they are dry, and stir in ½ tablespoon of flour to coat the berries.This helps prevent the berries from sinking to the bottom of the muffins while they bake
½ tablespoon all-purpose flour, 2 cups blueberries
Add the crushed and whole berries to the batter along with the lemon zest, if using, and fold into the batter, without stirring too many times.
½ tablespoon lemon zest
If using frozen blueberries: combine all the frozen blueberries with ½ tablespoon flour, stirring gently to coat. Add to batter along with the lemon zest, if using. Stir very gently, turning only a few times to ensure the blueberries don’t burst and color the batter completely blue/purple. The batter will be streaked blue/purple more than if using fresh berries
2 cups blueberries, ½ tablespoon all-purpose flour, ½ tablespoon lemon zest
Evenly distribute the batter amongst 6 jumbo muffin cups or 12 standard muffin cups. They should be filled almost to the top
Set aside to rest for 10 minutes This allows the batter to thicken, making for big beautifully risen muffin tops.
Sprinkle the tops of the muffin batter generously with sugar
¼ cup granulated sugar
Bake for 7 minutes at 425ºF, then lower the oven temperature down to 350ºF for another 15 minutes for standard muffins and 25-30 minutes for jumbo (mine take 35-36 mins total), or until a toothpick inserted into the center of the center muffin comes out clean
Allow to cool in muffin tins for 10 minutes, then transfer to a wire rack to cool completely