Filet Mignon with Stroganov Sauce
from Gourmet magazine - serves 4

The sauce tastes fine until you add the sour cream, at which point it becomes a thing of beauty and tastes divine.
The thickness of your filets will determine your cooking time. I like steaks that cook quickly, so I have no qualms about slicing the steak along it's equator, dividing it horizontally into two shorter but even pieces.
6 oz. dried egg noodles
1 medium onion, halved lengthwise
2 tablespoons canola oil
4 beef tenderloin steaks (filet mignons)
salt & pepper
2 cloves garlic, thinly sliced
 1/2 pound sliced white mushrooms
1/4 cup brandy (Madeira would probably be fine)
3/4 cup beef stock
2 tablespoons Worcestershire sauce
3/4 cup sour cream
1 Cook noodles in a 6- to 8-quart pot of boiling salted water until just tender. Drain in a colander.
2 Meanwhile, thinly slice onion. Heat oil in a 12-inch heavy skillet (preferably cast-iron) over high heat until hot but not smoking. While oil heats, pat steaks dry. Sprinkle with salt and pepper, then add to skillet and sauté, turning over once with tongs, until cooked to your desired degree of doneness (you can butterfly the filets, slicing horizontally through the center for thinner pieces that will cook faster). Transfer to a plate with tongs.

3 Add onion and garlic to skillet and season with salt and pepper. Sauté, scraping up any brown bits with a wooden spoon, until onion begins to brown, about 3 minutes. Add mushrooms and sauté, stirring occasionally, until liquid given off by mushrooms is evaporated, about 4 minutes.
4 Add brandy and boil until evaporated, about 1 minute. Add broth and Worcestershire sauce, then cook until onion is softened, about 4 minutes.
5 Remove from heat and stir in sour cream. Taste, and add more salt or pepper if desired. Toss noodles with some of the sauce and serve remaining sauce over the steaks.