This is one French variation on the hamburger. Another, called bifteck haché à cheval—or chopped steak on horseback—is so named for the fried egg "cowboy" perched atop the beef.
- 10 tbsp. butter, softened
- 1 medium yellow onion, peeled and finely chopped
- 1 1⁄2 lb. ground beef or chuck
- Leaves from 1 small sprig fresh thyme, chopped
- 1 egg, lightly beaten
- Salt and freshly ground black pepper
- 1⁄2 cup flour
- 1 tbsp. vegetable oil
- 1 shallot, peeled and minced
- 1⁄2 cup red wine
- Leaves from 6 sprigs parsley, chopped
Melt 2 tbsp. of the butter in a medium skillet over medium heat. Add onions and cook, stirring often, until soft, about 10 minutes. Transfer onions to a large bowl and set aside to cool. When cool, add meat, thyme, egg, 2 tbsp. of the butter, and salt and pepper to taste and beat with a wooden spoon until well combined. Divide meat mixture into 6 equal parts, then shape each into a 3 1⁄2" patty. Put flour into a dish, dredge patties, shaking off excess, and set patties aside.
Heat oil and 1 tbsp. of the butter together in a large heavy skillet over medium-high heat. Add patties and sear until well browned on both sides, turning once, 2-3 minutes per side for medium rare. Transfer patties to a warm platter and loosely cover with foil.
Discard fat from skillet and return skillet to medium heat. Melt 1 tbsp. of the butter in skillet, then add shallots and cook, stirring constantly, until they begin to brown, about 1 minute. Increase heat to medium-high, add wine, and cook, scraping browned bits stuck to bottom of skillet with a wooden spoon, until reduced by three-quarters, about 2 minutes. Remove skillet from heat and add the remaining 4 tbsp. butter, 1 tbsp. at a time, stirring constantly, until butter is melted and sauce is thick and velvety, about 1 minute. Add parsley and season to taste with salt and pepper. Spoon sauce over patties.