Zrazy Zawijane (polish Beef Roulade in Sour Cream Sauce)
5 tablespoons unsalted butter
3 tablespoons vegetable oil
3 cups onions, finely chopped
1 1/2 lbs mushrooms, finely chopped
1/4 cup soft breadcrumbs, from home-style bread, shredded
1 teaspoon salt
1/2 teaspoon pepper
2 lbs top round steaks, trimmed of fat & pounded to 1/4 " thick
2 teaspoons Dijon mustard
3 tablespoons flour
1 cup beef stock
2/3 cup sour cream
Preheat oven to 350°F.
In a heavy skillet, melt 2 tablespoons butter with 1 tablespoon oil over medium heat.
Saute the mushrooms and onions until the liquid in the pan starts to evaporate (8-10 minutes) (Do NOT let the mushrooms brown).
Stir in the bread crumbs and half of the salt and pepper; remove from heat.
Cut the steak into 8 rectangular pieces 3-4" wide by 6-8" long, sprinkle both sides evenly with remaining salt and pepper.
Spread a thin layer of the mustard on each slice of beef, and place 1/8 of the stuffing on the shorter end of each piece of steak.
Roll the steaks into cyclinders, enclosing the stuffing, and tuck in the sides; secure each end with kitchen cord.
Roll the zrazy in flour and vigorously shake off any excess.
In a heavy skillet, melt remaining butter with oil over high heat, and brown the rolls, turning them often so they evenly turn a rich golden brown without burning (about 15 minutes).
As they brown transfer them to a casserole dish large enough to hold them all in a single layer.
Pour off all but a thin layer of fat from the skillet and replace it with the beef stock.
Bring to a boil over high heat, stirring constantly (scraping the bottom and sides of the pan).
Pour the broth over the rolls and cover tightly.
Braise in the oven until the meat is so tender that it gives no resistance when pierced with the tip of a skewer or knife (45 minutes).
Remove the zrazy from the casserole dish, cut the cord off and cover with tin foil to keep the rolls warm while you make the sauce.
Skim off and discard as much of the fat as possible from the liquid remaining in the casserole dish.
Return to a boil over high heat, stirring constantly.
Remove from heat, and mix in the sour cream.
Season to taste and serve over zrazy.