Prep and preheat: Heat your oven to 425°F (220°C). Line a 12-cup muffin tin with paper liners or lightly grease the cups.
Mix dry ingredients: In a large bowl, whisk together flour, baking powder, baking soda, salt, and sugar. This helps distribute leavening evenly.
Whisk wet ingredients: In a separate bowl, whisk oil, melted butter, eggs, buttermilk, vanilla, and lemon zest until smooth. The mixture should look creamy and well combined.
Combine gently: Pour the wet ingredients into the dry. Using a spatula, fold just until you see a few streaks of flour. Do not overmix or the muffins will be tough.
Toss berries: In a small bowl, toss blueberries with the reserved 1 tablespoon of flour. This helps keep them from sinking.
Fold in berries: Add blueberries to the batter and fold gently a few times. It’s okay if the batter is thick and slightly lumpy. Avoid smashing the berries.
Fill the pan: Divide the batter evenly among the muffin cups, filling them nearly to the top for tall domes. Sprinkle each with a pinch of sugar.
Start hot: Bake at 425°F (220°C) for 5 minutes to jump-start the rise.
Finish baking: Without opening the oven, reduce the temperature to 350°F (175°C) and bake 12–15 minutes more, until the tops are golden and a toothpick comes out with a few moist crumbs.
Cool briefly: Let muffins cool in the pan for 5 minutes, then move them to a wire rack. Enjoy warm or at room temperature.
