Preheat oven to 425°F and line a muffin tin.
Toss blueberries with 1 tbsp flour; set aside.
Whisk dry ingredients (2 cups flour, sugar, powder, soda, salt) in a large bowl.
Whisk wet ingredients (buttermilk, oil, eggs, zest, juice, vanilla) in a medium bowl.
Fold wet into dry until just combined; fold in blueberries.
Fill muffin cups; bake at 425°F for 5 mins.
Lower heat to 375°F (without opening door) and bake 13–15 more mins.
Cool 5 mins in pan, then transfer to a rack.