Ingredients

• 4 (1 1/2-inch-thick) filets mignons (beef tenderloin steaks; each about 6 oz)
• 1 teaspoon salt
• 3/4 teaspoon black pepper
• 1 tablespoon vegetable oil
• 1 tablespoon unsalted butter
• 1 cup thinly sliced onion (1 large)
• 1/2 teaspoon finely chopped garlic
• 10 oz mushrooms, sliced
• 1 tablespoon paprika (not hot)
• 2/3 cup sour cream
• 1 tablespoon Dijon mutard
• 2 teaspoons Worcestershire sauce
• Accompaniment: buttered egg noodles

Instructions

1. Pat beef dry and sprinkle with 3/4 teaspoon salt and 1/2 teaspoon pepper. Heat oil in a 10- to 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté beef, turning over once, about 10 minutes total for medium-rare. Transfer beef to a plate and let stand, loosely covered with foil, 10 minutes.
2. While steaks are standing, heat butter in same skillet over moderate heat until foam subsides, then cook onion, stirring occasionally, until softened, 3 to 5 minutes. Add garlic, mushrooms, and remaining 1/4 teaspoon salt and 1/4 teaspoon pepper and cook, stirring constantly, until liquid mushrooms give off is evaporated, 3 to 5 minutes. Add paprika and cook, stirring constantly, 1 to 2 minutes. Stir in sour cream, mustard, and Worcestershire sauce and bring just to a simmer (do not let boil). Stir in any beef juices accumulated on plate and thin sauce with up to 1/4 cup water if necessary.
3. Spoon sauce over steaks and noodles.