Meanwhile, use 3-1/2-inch cookie cutter to cut each tortilla into 4 rounds. Mix sugar and cinnamon. Brush both sides of tortilla rounds with butter; sprinkle with sugar mixture. Bake 5 to 8 min. or until lightly browned. Immediately transfer tortilla rounds to hang over round handles of large wooden spoons placed over top of large bowl to form taco shells. Cool completely.