Sprinkle beef evenly with salt and pepper. Place in an aluminum foil-lined roasting pan.
Bake at 450° for 15 minutes.
Melt butter in a medium saucepan over medium heat. Add onion, garlic, and mushrooms. Cook, stirring often, 7 minutes. Stir in wine and next 3 ingredients. Whisk together beef broth and all-purpose flour, and stir into wine mixture. Reduce heat, and simmer, stirring occasionally, 10 minutes or until onion is tender.
Remove beef from oven, and top with sauce. Bake beef 18 more minutes or to desired degree of doneness, basting once. Transfer beef to a serving platter, reserving sauce in pan. Let beef stand 10 minutes before slicing.