Melt the butter in large saucepan over low heat. Add the onion, celery and garlic and saute until the onions become translucent, about 4 to 5 minutes. Add freshly cracked white pepper and stir in the flour to make a light roux. Set the roux aside.
In another saucepan, over low heat, combine the clam juice and the half-and-half. Heat slowly until the mixture almost comes to a simmer.
Slowly whisk the clam juice mixture into the roux. Stir in the sherry and fold in the crabmeat. Add seafood seasoning, to taste. Slowly reheat the sauce. (DO NOT BOIL!) If necessary, add milk to desired consistency. This should be a thick soup, so go slow with the milk.
Ladle the soup into small serving bowls and top each with a dollop of masago. Grate fresh nutmeg on top and serve with crostini.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.