In a bowl combine flour, baking powder, sugar and salt, whisk to blend

In another large bowl add milk and lemon juice, whisk and let sit 1 minute

Whisk in egg, butter and vanilla

Stir in flour mixture until mostly smooth, the batter will be thin. Don't be tempted to add more flour, they will puff up light and tender in the oven

Fill mini muffin pans 2/3 full with batter

Add 2 to 3 fresh blueberries to each muffin. 3 if the bleberries are small, 2 if large

Bake 9 to 10 minutes until puffed and golden and a toothpick inserted in area without a blueberry comes out clean

Cool on pans about 1 to 2 minutes before removing to a rack to cool. Run a thin knife around any that stick to pans to remove.

Serve with warm maple syrup for serving