how to make burger

1 1/2 lb. ground beef
1 tsp. salt
1/4 tsp. pepper
1 1/2 c. onion, chopped
2 tbsp. butter
2 tsp. horseradish, prepared
2 tsp. mustard, prepared
1/2 tsp. salt
6 split buns

Combine ground beef, salt and pepper. Shape into 12 thin patties. Brown chopped onion lightly in butter, add horseradish, mustard and salt.Spread onion mixture over 6 patties, top each with a patty and press together to form 6 large patties. Chill.
Place patties on grill and brown each side 8 to 10 minutes.
Serve on buns, if desired.