Burgers are standard Labor Day fare, and while there’s nothing wrong with the classic interpretation, it can be fun to mix things up with contrasting flavors and textures. Rather than serve your burgers on the usual soft bun with a slice of melted cheddar, stuff the beef and cheese into pita halves and fry them to give your burger a perimeter of crispy fried cheese. In this recipe from our cookbook “ Milk Street 365: The All-Purpose Cookbook for Every Day of the Year,” we season the beef with yellow mustard for spicy tang and dill pickles for brininess, then fill pita halves with the mixture, forming a thin layer, along with sliced onion and cheese. The cheese hits the skillet when the sandwiches are pan-fried, crisping and developing flavorful browning, and creating an irresistible layer that complements the juicy patties.