4 lbs snow crab clusters (legs)
4 quarts water - (16 cups)
1 small onion, chopped
1 1/2 celery stalks, chopped
2 garlic cloves, quartered
2 small turnips, peeled, chopped
1/4 cup fresh chopped Italian parsley
2 tsp mustard seed
1 Tbs chopped pimento
1/2 tsp coarsely-ground black pepper
2 bay leaves
1/3 cup sugar-free tomato sauce
2 Tbs half-and-half
1/4 cup unsalted butter
1/4 tsp thyme
1/8 tsp basil
1/8 tsp marjoram


Remove all the crab meat from the shells and set it aside.
Put half of the shells into a large pot with 4 quarts of water over high heat. Add onion, 1 stalk of chopped celery, and garlic; then bring mixture to a boil. Continue to boil for 1 hour, stirring occasionally (the white part of the shells will start to become transparent), then strain stock. Discard the shells, onion, celery and garlic, keeping only the stock.
Measure 3 quarts (12 cups) of the stock into a large sauce pan or cooking pot. If you don't have enough stock, add enough water to make 3 quarts.
Add turnips, bring mixture to a boil, then add 1/2 of the crab and the remaining ingredients to the pot and bring it back to boiling. Reduce heat and simmer for 4 hours, uncovered, until it reduces by about half and starts to thicken. Add the remaining crab and simmer for another hour until the soup is very thick.