To assure the quality of texture and rising of the butter do not omit using the ingredients that are room temperature. Resting the butter before baking is just as important. Starting the baking process with a higher temperature (425F) lets the tops rise faster and wider. Make sure to lower the temperature to 400F after the initial 5min. Otherwise your muffins will burn. Here is My favorite Jumbo Muffin Pan (paid link)