Start with 6 sheets filo dough (about 12 by 18 in.) and 1/3 cup butter or margarine, melted. Lay 1 filo sheet flat (cover remaining filo with plastic wrap to prevent drying) and brush lightly with butter. Top with another filo sheet and brush lightly with more butter. Repeat to stack remaining filo.
Cut filo to fit the top of a 1- to 2-quart shallow casserole. Gently transfer filo to a buttered baking sheet (11 by 14 in.). Bake in a 400° oven until golden brown all over, 3 to 4 minutes.
Heat 3 cups prepared chili or stew, pour into casserole and top with crust.