Cream masa with butter. Mix hot water and broth, stirring to dissolve powder. Add enough broth to masa to make a thick batter; stirring well. Add additional broth or hot water until you have a thick but pourable batter. Brown ground beef thoroughly in a skillet or frying pan. Drain off excess fat. Transfer to a greased casserole dish, deep pie plate, or keep it in the iron skillet. Add beans and layer onion, pepper, ½ cup grated cheese, and corn over beans; spoon salsa over all. Spread batter over top of salsa. Bake, covered, for 30 minutes at 350°F. Uncover, sprinkle remaining cheese over top and bake another 20 minutes, until browned. Serve with hot sauce & sour cream.