Flat muffins with no tops?

Exactly the opposite of the problem described directly above, in this case, you might want to consider raising the oven temperature 25 degrees. Additionally, make sure your batter isn’t too runny; it should definitely be thicker than cupcake batter. Don’t be shy when you fill the tins, because unlike cupcakes, you want to mound these up right to the top, and possibly even over. Make sure you do pile on the batter right in the center, to encourage those golden-brown peaks to form.