In a large heavy-bottomed pot, melt the butter over high medium heat, then reduce heat to medium. Sauté the onion and celery until soft while stirring with a wooden spoon, about 5 minutes.
Whisk in the flour, and cook for 2 minutes.
Slowly pour in the seafood stock, whisking continuously so the crab soup remains smooth. Add the heavy cream while whisking, then repeat with the whole milk.
Stir in the white crab meat, sherry, and spices.
Turn the heat down to medium low to allow it to simmer for 5 to 8 minutes, then taste and adjust seasonings if needed.
Serve hot, and garnish each bowl with paprika, chives, freshly grated Parmesan cheese, or oyster crackers.
To warm up leftovers, pour soup into a pot set over medium heat, stirring frequently so the bottom doesn't burn.