1 to 1-1/2 pounds beef tenderloin
Salt and freshly ground pepper to taste
4 tablespoons butter, divided
4 large garlic cloves, finely minced
1 medium onion, chopped
1 teaspoon dried thyme
1 tablespoon all purpose flour
2 cups beef broth
2 cups dry red wine
Cut tenderloin crosswise into 12 equal rounds. Pound beef rounds to flatten to generous 1/4-inch-thick medallions. Season lightly with salt and pepper.
Melt 2 tablespoons butter in heavy large skillet over medium-high heat. Working in batches, cook beef in skillet until brown on outside but still pink in center, about 2 minutes per side. Transfer beef to plate. Add remaining butter to same skillet.
Add garlic, onion and thyme to skillet; saute until tender, about 3 minutes. Add flour; stir 1 minute. Add broth and wine. Boil until sauce thickens and is reduced to 1-1/4 cups, stirring occasionally, about 12 minutes. Return beef and any collected juices to sauce in skillet; heat through, about 1 minute.
Serves 4.