From Cook's Illustrated. When fresh blueberries are not in season, frozen blueberries are a good alternative. To make sure that frozen berries do not bleed, rinse them under cool water in a mesh strainer until the water runs clear, then spread them on a paper towel-lined plate to dry. If you have buttermilk on hand, use 2 cups of buttermilk instead of the milk and lemon juice. 1 cup blueberries = 16 T, 1 T per pancake. If you like more blueberries, as my husband does, double the quantity of blueberries and use 6-8 blueberries per pancake. Also, I use a 1/3 cup measure to get slightly larger pancakes.