We make our blueberry muffins with fresh blueberries only. So earmark this recipe for early summer, when the first crop of berries comes into the markets. You might be wondering what an apple is doing in the batter. It's adding moisture to an unusual muffin batter- one with two kinds of flour, both brown and white sugar, buttermilk, and the subtle flavor of mace. These are tender and luscious. You won't even need butter.