Burgers Smothered in a Caramelized Onion, Mushroom and Blue Cheese Sauce

What you will need

1 1/2 pound ground beef

salt and pepper to taste

4 buns

1/2 cup caramelized onion, mushroom and blue cheese sauce (see below)

4 leaves lettuce

4 slices tomato

2 tablespoons butter

1 onion, sliced

2 cloves garlic, chopped

1 teaspoon thyme, chopped

8 ounces mushrooms, sliced

salt and pepper to taste

1 splash brandy

1/4 cup beef broth

1/2 cup blue cheese, crumbled