Boil eggplant until tender, approximately 30 minutes. Peel; cut in half; remove seeds and chop finely. Wet bread; let stand. Saute both kinds of onions in butter until clear.
Add chopped raw shrimp and simmer about 10 minutes. Squeeze moisture out of bread and chop. Add bread to shrimp mixture and cook a few minutes. Add chopped eggplant, salt and pepper to taste, and 1 slightly beaten egg.
Prepare sauce by cooking onion in butter until soft. Blend in flour. Add milk. Stir till thick. Remove from heat. Add seasoning. Blend sauce into shrimp-eggplant mixture. Spoon into shell and bake at 350 F until lightly brown. Sprinkle with parsley.