Entrecote Steak with Mushrooms and Whole Onions
Preheat the oven to 180°C (approximately 350°F).
Trim and slice the mushrooms. Heat 1 tablespoon oil and 1 tablespoon butter and saute the mushrooms over high heat. Just before to release water, remove from the heat. Season with salt and pepper.
Trim the ends of the onions cut and only remove the outer shells. Place 2-3 tablespoons oil in a baking dish, add the onions and cook in the oven about 30 minutes.
Heat 2 tablespoons oil in a pan and sear the steak 3-5 minutes on each side (medium) depending on thickness. Remove the steaks from the pan and keep warm. Add the beef stock and wine to the pan drippings. Bring to a boil and reduce by half, then stir in 1 tablespoon cold butter. Season with salt and pepper. Arrange the steak with the onions on plates. Heat the mushrooms again briefly, place on top of the steak, and drizzle with the sauce. Serve immediately.