No, Frito pie wasn't invented in a double-wide disposal. Daisy Dean Doolin, mother of Elmer Doolin, the Frito Company founder, concocted the recipe in the kitchen of her San Antonio home way back in 1932 in the depth of the Great Depression. At Sonny Bryan's downtown tunnel location, they substitute chopped brisket for ground beef in the $4.99 Thursday Frito pie special, and it makes for a monster dish. The beef is mixed with Fritos corn chips, barbecue sauce, beans, chives and cheese. You also get a small drink. Dave "The Baron of Beef" Rummel, the store's manager, says Thursdays have become the shop's biggest day of the week partly because of the rising popularity of this down-home dish. Ham, sausage, chicken and the very tasty pulled pork are featured the other days of the week. In these lean times, Mrs. Doolin's hearty invention should keep you feeling fat until dinner, if not into the middle of next week.