Separate scallops from corail and cut scallops widthwise into 3 equal slices each. Clean mushrooms and cut into very thin slices. Finely chop shallot, garlic and parsley. Briefly scald tomato, peel, core and dice. Heat butter and olive oil in a small pan. Sauté scallops and corail in it for about 1 minute, remove and keep warm. Reduce heat slightly and sauté shallots in pan drippings until translucent. Add mushrooms and tomatoes, season with freshly ground pepper and pour in rosé wine. Reduce wine to about a third of its volume. Add garlic, parsley and scallops and let simmer in sauce for 1 more minute over medium heat. Season to taste with freshly ground sea salt and pepper. Remove pan from heat and stir the ice cold butter into the sauce. Serve hot.