While the batter is resting, preheat the oven to 425°F. Line a 12-cup muffin pan and lightly grease the liners.
After the batter has rested, stir in the blueberries. Divide the batter into the muffin pan.
Bake at 425°F for 6 minutes, then reduce the oven temperature to 350°F and bake for another 15 minutes or until a toothpick inserted in the center comes out clean.
Place the muffin pan on a wire rack to cool for 5 minutes, then carefully remove the muffins and place directly on the wire rack to finish cooling.