In a food processor, process the fish, hard boiled egg and onion in the food processor until smooth. Add salt, matzo meal and sugar, eggs and water then mix until well combined. Refrigerate for at least an hour.
In a large stock pot mix fish skin, bones and heads with onions, carrots, celery and parsnip. Add cloves, salt and pepper. Cover with about 1 1/2 litres of water. Cover, bring to a boil then allow to simmer for about 30 minutes.
Strain the stock throw away the bones and veggies. Return stock to stockpot.
Remove fish from refrigerator and form into oval balls. (It is easiest to do this with wet hands).
Bring broth back to a simmer over medium low then add the fish balls, cover then simmer until fish is firm and cooked through, about 20 minutes.
Remove fish and set in casserole dish or into jars. Strain stock though muslin or cheesecloth into a bowl then pour over fish, cover then refrigerate overnight.