Spread toast rounds with tartar sauce; set aside. In nonstick skillet over high heat, saute mushrooms and garlic in water and white wine until liquid has evaporated. Remove from heat and cool for 15 minutes. Transfer to medium size bowl. Mix mushroom mixture and lobster together. Sprinkle mixture equally over tartar sauce on each round and dust with paprika. Chill in refrigerator for one hour.
Fifteen minutes before chilling is complete, combine horseradish, cheese and mayonnaise, mix well. Press mixture through pastry bag and place a border on each round. In center of each canape, place a sprig of watercress.
Makes dozen servings.
Calories 80ºC at 0.6 g Fiber 0.6 g.