World'S Greatest Mushroom-Onion Burgers - cooking recipe

Ingredients

4 tablespoons butter or 4 tablespoons margarine
1 large onion, chopped
6 ounces mushrooms, chopped
1 1/2 lbs ground sirloin
1 1/2 teaspoons salt
1 teaspoon fresh ground black pepper
1 tablespoon A.1. Original Sauce
flour (for dredging)
2 tablespoons olive oil (preferably extra-virgin)
5 large kaiser rolls, lightly toasted
Accompaniments
cheese, of your choice (optional)
sour cream (optional)

Preparation

In a large, heavy skillet, melt butter or margarine.
Cook onions over medium-low heat until golden brown.
Add the mushrooms and continue cooking until mushrooms are tender.
Let sit until cool enough to handle.
In a large bowl, mix the sirloin, salt, pepper, steak sauce, and onion-mushroom mixture.
Form into 5 burgers.
In same skillet, heat olive oil over medium heat.
Dredge burgers in flour and cook until desired doneness, turning once.
Add cheese (if desired) and melt atop burger.
Top with a dollop of sour cream.