If you want tall, fluffy muffins be sure to have your egg, butter, and milk at room temperature before you start your batter. Fill your muffin cups all of the way to the top of the tin with a thick muffin batter. Blast the muffins in the oven at a high temperature (400°F) for 5 minutes to create a "rise" to the muffin and then reduce the temperature to what the recipe card calls for and bake until the muffins are done.