Place the smoked haddock in a pan a little large than the fish itself. Sprinkle with peppercorns, thyme, parsley, the small onion, and celery leaves. Pour in the stock. Add 1 cup heavy cream and milk. Cover pan with aluminum foil and place pan in a 350 degree F oven for 15 minutes or until the fish is barely heated through, turning opaque. Remove from oven. Let cool.
Flake the fish into big pieces, making sure there are no bones or whole peppercorns lurking in crevices.
Blanch 6 (1 pound) culls in boiling salted water for 5 to 6 minutes. Refresh in cold water to stop cooking. Take meat from the shells leaving big chunks.
In a 3-quart stainless saucepan, place 4 of the lobster bodies over medium heat with 2 tablespoons butter. Saute until barely colored, then add 2 cups heavy cream and simmer slowly until reduced by 1/3. Use any of the smoked haddock scraps, bones, etc., when reducing the cream. This will give additional flavor to the soup. The lobster cream should have a lobster-smoked haddock flavor.
Add the stock cream from poaching the smoked haddock. Strain, you should have approximately 3 to 3 1/2 cups soup base.
To finish soup, saute 1 medium size onion in 4 tablespoons of butter. Add 4 red bliss potatoes cut into chunks leaving skins on. Pour over the soup base and simmer until the potatoes are just done , not overcooked and mushy. Season with salt and freshly ground black pepper.
In saute pan over medium heat, saute lobster meat, in big chunks in 2 to 3 tablespoons of butter. Add to the soup with the finnan haddie, taste for any additional salt and pepper. Adjust the amount of liquid by adding milk or cream. Bring just to a boil, heating the fish and lobster through. Ladle into hot soup bowls. Place a little slice of whole butter to melt on top and plenty of finely chopped parsley for garnish.
Serve with toasted and buttered split Vermont common Crackers. If you can not find the crackers use Old Fashioned Cream Biscuits or hot bread.