Combine all filet ingredients except butter and seasoned salt. Shape into six patties 1 1/2 inches thick.Press 1 teaspoon of the butter into center of each enclosing well.Wrap a strip of foil,1 1/2 inches wide,around,folding over ends to secure. Sprinkle both sides with seasoned salt.Chill while preparing mushrooms and sauce. Melt 1 tablespoon of butter in medium fry pan.Saute mushroom caps.Set aside.Wipe out pan for sauce. Make sauce by combining all ingredients and simmer 10 minutes, until slightly thickened.Keep warm. Heat remaining butter about 4 tablespoons in large heavy fry pan.Cook filets 3 to 3 1/2 minutes on each side,slightly pink in center.Remove foil strips.Place on toast points on serving plate.Spoon on sauce and top with mushroom caps.Garnish. Serves 6.