Cut squash in half; discard seeds. Place cut side down in a 15x10x1-in. baking pan; add 1/2 in. of hot water. Bake, uncovered, at 400° until tender, about 30 minutes. , When cool enough to handle, scoop out flesh, leaving a 1/4-in. shell (flesh will measure about 3 cups). Drain water from pan; place squash cut side up in pan and set aside. , In a large bowl, combine the flesh, egg, salt and pepper. Dissolve bouillon in boiling water; add to squash mixture. Add stuffing; spoon into squash shells. If desired, top with cheese. Sprinkle with paprika. Bake, uncovered, at 400° until heated through, 20-25 minutes. If desired, top with chopped parsley.