Put the bread into a small bowl and sprinkle with the water. Blend well to dampen the cubes. Put the carp roe into the bowl of an electric blender. Add the bread cubes, lemon juice, garlic, and onion. Blend well on high speed, gradually adding the oil in a thin stream, until all of the oil is used. Garnish with parsley and serve over the toast. Makes 6 servings