The crossword solutions for the term 'STUFF IN A MUFFIN' are BRAN (4 letters) and BRA (3 letters). BRAN is a type of cereal grain made from the hard outer layers of wheat or other grains. It is high in dietary fiber and essential minerals, and is often used in baking. BRA is an abbreviation for brassiere, which is a type of undergarment worn by women to support their breasts. Both BRAN and BRA can be used as ingredients in muffins, making them a popular choice for stuff in a muffin.