A store the size of a shoe box, limited seating and a cash-only policy have done little to hold off the morning hordes from this immensely popular muffin shop. Tray upon tray of steaming muffins are served up by the owners who have kept Tufts students and Somerville locals dropping in each morning for 10 years. Although muffins are the specialty, don't miss the bagels, breakfast sandwiches or hot coffee either.