Toss the blueberries in flour before adding them to the batter; this will allow them to suspend evenly through the muffins instead of sinking to the bottom. Fold the berries gently into the batter to avoid turning it blue.
From the book "Mad Hungry," by Lucinda Scala Quinn (Artisan Books).
These muffins are best eaten still warm from the oven. If you need to make them a day ahead, store them in an airtight container, and reheat in a 350 degree oven for about ten minutes. The batter can also be used to make coffee cake; bake it in an eight-inch springform pan for about forty minutes.