1 lb. lean ground beef
1 onion, minced
2 tsp. mustard
Salt and pepper
1 cup cheddar or American cheese, grated (about 1/4 lb.)
1 tbsp. ketchup
2 scallions, sliced
4 hamburger buns, toasted

Step 1
In a large bowl, mix the beef, onion, mustard, salt and pepper. In a small bowl, mix the cheese, ketchup and scallions. Divide the ground beef into 8 equal portions and flatten these into patties. Spread 4 of them with cheese mixture and top with the other 4 patties. Wet the edges and press them together to enclose the filling.

Step 2
Cook the burgers under a hot broiler, in a heavy skillet or on a grill until they are cooked through, at least 5 minutes to a side. Serve on toasted buns. Makes 4 servings.