Another burger idea that won rave reviews! Everything is cooked in just one cast iron skillet. The rosemary pairs well with the beef and with the addition of mushrooms cooked with beef broth make this a burger very worthy of company.
1 lb. lean ground beef
1 small shallot, minced and dived about 3 T. total
1 T. fresh rosemary, minced and divided
1 T. Worcestershire sauce
salt and pepper
1 T. extra virgin olive oil
4 slices Swiss cheese
2 T. butter, divided
8 oz. sliced mushrooms
1 clove garlic, minced
1 cup beef broth
Combine ground beef, 2 T. shallots, 2/3 of the minced rosemary, Worcestershire sauce, salt, and pepper in a large bowl and lightly mix until combined. Create four burger patties and then set aside.
Heat olive oil in a very large (10-12") cast iron skillet. Add burger patties and cook 4 - 5 minutes per side for burgers cooked to medium.
Add Swiss cheese slices then allow to melt slightly (don't let cheese melt into the skillet or it will burn). Transfer to a plate then loosely tent with a piece of foil.
Melt 1 T. butter in skillet then add mushrooms and remaining tablespoon of shallots. Season with salt and pepper then sauce until mushrooms are golden brown, 5 minutes or so.
Add remaining rosemary and garlic and saute for another minute or so.
Add beef broth, then simmer, scraping the bits up from the bottom of the pan, until sauce has reduced and thickened slightly, 5 minutes.
Add remaining 1 T. butter and stir until melted. Place burgers on buns and then top with mushrooms and sauce.
From Iowa Girls Eats