BEEF WITH MUSHROOMS AND GLAZED ONIONS

Steps:

• Place marrow bones in large bowl. Cover with ice water. Refrigerate overnight. Drain bones. Using small sharp knife, push marrow out through bones. Coarsely crumble enough marrow to equal 1 1/4 cups. Reserve bones and any remaining marrow for another use.
• Boil stock, wine and Port in heavy large saucepan until liquid is reduced to 1 1/4 cups, about 30 minutes.
• Preheat oven to 450°F. Sprinkle steaks with salt and pepper. Heat 1 tablespoon oil in heavy large skillet over medium-high heat. Working in batches, add steaks to skillet and cook until brown, about 2 minutes per side. Transfer steaks to rimmed baking sheet. Cook steaks in oven to desired doneness, about 8 minutes for medium-rare. Tent with foil to keep warm.
• Meanwhile, discard excess oil in skillet. Whisk reduced stock mixture into skillet. Bring to boil, scraping up any browned bits. Strain sauce into small saucepan; discard solids. Add reserved 1 1/4 cups crumbled marrow to sauce; stir until melted. Keep sauce warm.
• Melt 3 tablespoons butter in another heavy large skillet over medium-high heat. Add mushrooms, shallots and garlic; sauté until mushrooms are golden brown and tender, about 10 minutes. Stir in tomatoes and parsley. Season mushroom mixture with salt and pepper.
• Spoon sauce onto plates. Place steaks atop sauce. Spoon mushroom mixture over steaks. Surround with Glazed Onions and serve.