Slice 1/2 lb. portobello, shiitake, or other "wild mushrooms. In a skillet over medium- high heat, melt 1/2 tablespoon unsalted butter with 1/2 tablespoon olive or canola oil. Add mushrooms and brown lightly. Add 2 tablespoons minced shallots and 2 large garlic cloves, finely minced; cook, stirring, 2 minutes. Season with coarse sea salt, freshly ground black pepper, and dash cayenne pepper. Set aside. Select a heavy skillet large enough to hold 6 ostrich fillets without touching and place over medium-high to high heat. Add 1/2 tablespoon unsalted butter and 1 tablespoon olive or canola oil. When foam subsides, add fillets and saut� quickly, turning once, until nicely browned on both sides, 1 to 2 minutes on each side. Sprinkle with coarse sea salt and freshly ground black pepper as you turn fillets and be careful not to overcook. Test as directed and transfer fillets to a heated platter. Pour off any fat in skillet and return to high heat. Add 1/2 cup beef stock and 1/2 tablespoon tomato paste. Cook, stirring up any browned bits on skillet bottom, until liquid is reduced to about 3 table-spoons. Add 1/3 cup dry red wine or Madeira and boil 2 minutes. Add reserved mushrooms to skillet, heat briefly, and pour over fillets. Sprinkle with minced fresh parsley and serve immediately.