In a large stockpot, combine chopped onions, celery stalks, peppercorns, bouillon cubes, and salt with 1 gallon of cold water and bring the water to a boil. Add the live lobster to the boiling stock, reduce heat, cover and simmer for about 10 minutes.
Remove the lobster from the stock and place it on the side to cool. While the lobster is cooling continue to boil the stock so that it may reduce.
When the lobster has cooled sufficiently to allow handling, shell it over a mixing bowl or pie plate taking special care to catch all the juices. Place the lobster meat on the side for later use. Return all the reserved juices, shells and otherwise inedible parts of the lobster to the lobster stock and boil until the stock has reduced by half.
In a separate stockpot, melt the butter, then add the flour to the butter making a roux. Cook the roux over a medium heat for about 1 minute while continually whisking. Add the tomato puree and cook for an additional minute.
Strain the lobster stock through a fine sieve. Add the lobster stock 1/2 cup at a time while whisking smooth. When the soup reaches the consistency of a gravy, reduce the heat and add the lemon juice, salt, Lea & Perrins, A1 Sauce, sugar, and white pepper and simmer for about 10 minutes while stirring.
Slowly add the light cream while stirring and bring the soup back to temperature. Adjust the seasoning. Chop or slice the reserved lobster meat into desired size and add to soup. Serve at once.Makes 4 Source: