Grilled Flank Steak With Shiitake Mushrooms - cooking recipe

Ingredients

Marinade
2 (1 1/4-1 1/2 lb) flank steaks, fat trimmed
1/2 cup soy sauce
1/2 cup oriental sesame oil
1/2 cup soy sauce
3 tablespoons red wine vinegar
fresh ground pepper
2 medium garlic cloves, crushed
Mushroom sauce
1 lb fresh shiitake mushroom, discard stems
3 tablespoons unsalted butter
3 tablespoons vegetable oil
2 cups unsalted beef stock (or more)
4 teaspoons Dijon mustard
4 teaspoons coarse grain mustard
1/2 cup heavy cream
salt & freshly ground black pepper
1 tablespoon unsalted butter
1 tablespoon vegetable oil

Preparation

Steaks;.
Place steaks in non aluminum pan (or ziploc bag) .
Whisk soy sauce,sesame oil, vinegar and generous amount of pepper in medium bowl; mix in garlic.
Pour over steaks, turning to coat all sides.
Cover pan tightly and refrigerate 24 hours, turning steaks occasionally.
Mushroom Sauce:.
Reserve 6 2-inch diameter mushrooms for garnish.
Cut remaining into 1/2-inch-wide strips.
Melt 3 tablespoons butter with 3 tablespoons oil in large heavy skillet over medium-high heat.
Add mushroom slices and stir 3 minutes.
Mix in 1 cup stock and both mustards; increase heat to high and boil until reduced by half, about 5 minutes.
Add 1 cup stock, 1/4 cup at a time, boiling until sauce is reduced by half after each addition.
Stir in cream and boil until sauce coats spoon, about 3 minutes.
*This can be prepared 1 day ahead. Chill sauce and reserved mushrooms separately.
Prepare barbeque grill (high heat). Steaks can also be cooked in broiler.
Remove steaks from marinade and arrange on grill rack.
Cook about 4 minutes per side for medium-rare.
Transfer to platter and let rest 5 minutes.
Reheat sauce over low heat, stirring occasionally.
Melt 1 tablespoon of butter with 1 tablespoon oil in heavy small skillet over high heat.
Add reserved mushroom caps and cook until heated through, about 2 minutes per side.
Drain mushroom caps on paper towels.
Cut steaks across grain diagonally into 3/8-inch slices and arrange in circular pattern on heated platter.
Thin sauce with additional stock if desired and ladle half of sauce in center of platter.
Arrange mushroom caps in 2 clusters on platter edge.
Serve immediately, passing remaining sauce separately.