These muffins are easy to make: Simply mix the dry and wet ingredients separately, then combine them. Since the baking powder, which lightens the muffins, is activated by moisture, get the batter into the oven immediately. For soft edges, use liners; for crisp edges, use a well-greased, unlined pan. You can easily replace the blueberries with other kinds of fresh fruit, such as raspberries or peaches (chopped into small pieces). In the off-season I used IQF (individually quick-frozen) fruit; there's no need to thaw.