Heat oven to 400 degrees Fahrenheit. For big-topped muffins, line 8 standard-size muffin cups with paper liners. For standard-size muffins line 10 muffin cups. Fill the remaining cups with 1 to 2 tablespoons of water to help the muffins bake evenly.
MAKE BATTER
Whisk the flour, sugar, baking powder, and salt in a large bowl.
Add oil to a measuring jug that holds at least 1 cup. Add the egg then fill the jug to the 1-cup line with milk (1/3 to 1/2 cup milk). Add vanilla and whisk to combine.
Add milk mixture to the bowl with dry ingredients then use a fork to combine. Do not over mix. (The muffin batter will be quite thick — see note below for more details). Fold in the blueberries.
BAKE MUFFINS
Divide the batter between muffin cups. (If making big-topped muffins, the batter will come to the tops of the paper liners). Sprinkle a little sugar on top of each muffin.
Bake muffins 15 to 20 minutes or until tops are no longer wet and a toothpick inserted into the middle of a muffin comes out with crumbs, not wet batter. Transfer to a cooling rack.
To store, place them in a plastic bag, seal, and store at room temperature for 2 to 3 days. To freeze, wrap them tightly in aluminum foil or place them in freezer bags. Freeze for up to 3 months.
TIPS
You can make these with fresh or frozen blueberries – if you use frozen, do not thaw the blueberries.
For mini muffins, the baking time will be less — keep an eye on them while they bake and expect them to require 9 to 11 minutes.
Batter Thickness: The batter should be thick and “scoopable” — not runny and not dry or extra thick like dough. If the batter is too runny, add flour, a tablespoon at a time until correct consistency. If the batter is dry or too thick, add milk, a tablespoon at a time until the proper consistency.
