Swiss Melt Mushroom Burgers - cooking recipe

Ingredients

1 1/2 lbs hamburger
1/4 cup finely diced onion
2 eggs, lightly beaten
3/4 cup soft breadcrumbs
1/4 cup ketchup
1/2 teaspoon salt
1/8 teaspoon freshly ground black pepper
2 tablespoons butter
1/2 lb mushroom, sliced
6 slices swiss cheese
12 slices dark rye bread, toasted

Preparation

Mix well the first 7 ingredients (meat through to pepper) and form into twelve 1/4-inch thick patties.
Melt the butter and saute the mushrooms lightly in it.
Place on 6 of the patties.
Top with remaining patties and seal edges.
Broil or grill to desired doneness.
Top with cheese.
Place each patty on a slice of toasted bread and top with another slice of toast.