Cut squash in half; discard seeds. Place cut side down in a 15-in. x 10-in. x 1-in. baking pan; add 1/2 in. of hot water. Bake, uncovered, at 400° for 30 minutes or until tender.
When cool enough to handle, scoop out pulp, leaving a 1/4-in. shell (pulp 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 pulp, egg, salt and pepper. Dissolve bouillon in boiling water; add to squash mixture. Add stuffing; spoon into squash shells. Top with cheese if desired. Sprinkle with paprika. Bake, uncovered, at 400° for 20-25 minutes or until heated through.Yield: 6 servings.