Use a 3 tablespoon sized cookie scoop to scoop the lemon and blueberry muffin batter into each of the muffin liners, alternating every other cup.
Bake the muffins at 425 F (205 C) for 5 minutes, then reduce the temperature to 350 (177 C) and bake an additional 12 - 14 minutes. Do not open the oven door to reduce the temperature.