Sauteed, Steakhouse-Style Mushrooms

Place a large, deep, heavy skillet over medium-high heat. When the skillet is hot, melt the butter, and swirl to coat the bottom of the pan. Add the mushrooms, garlic, and sweet onions. Toss gently to coat the vegetables in the butter. Sprinkle with salt, and cook, stirring occasionally, until the mushrooms release their liquid, about 5 minutes. Continue to saute until the liquid has almost evaporated. Add the red wine and beef stock. Reduce the heat, and simmer until the liquid has reduced by half, about another 5 minutes. Taste, and add additional salt and pepper if needed. Serve as a side with broiled or grilled steaks or as a side dish for any protein entree.