Food editor Paul Grimes credits his cooking-school teacher chef Fernand Chambrette of école de Cuisine La Varenne, in Paris, with teaching him how to waste nothing and how to coax flavor even out of scraps. But this is not just an exercise in virtuosity, since the butter carries every last drop of sweet sea essence rendered from the shells. Keep any extra in your freezer and scoop some out whenever you want to punch up a seafood dish.
Cooks' note:
Crab butter keeps, covered and chilled, 2 days or frozen in an airtight container 3 months.