Shrimp and Crab Gumbo

Preparation

1. Step 1

   In a 4-quart saucepan simmer reserved shrimp shells, bay leaf, and water, partially covered, 15 minutes and strain through a sieve into a bowl. Return shrimp stock to pan and keep warm.

   Step 2

   In a heavy skillet (preferably cast-iron) cook oil and flour over moderately low heat, stirring constantly with a flat-edged metal or wood spatula, until roux is a couple of shades darker than peanut butter, about 30 minutes. Stir in onion, bell pepper, and celery and cook, stirring occasionally, until vegetables are softened.

   Step 3

   Stir roux into stock and bring to a boil, stirring. Add crab legs and simmer, partially covered, stirring occasionally, 15 minutes. Stir in rice and tomatoes and simmer, stirring occasionally, 12 minutes.

   Step 4

   Transfer crab legs to a work surface. Cut shells open with kitchen shears and remove crab meat, discarding shells and cartilage. Tear crab meat into bite-size pieces and stir into gumbo. Add shrimp and simmer until just cooked through, about 3 minutes. Stir in scallion greens, cayenne, and salt and pepper to taste. Gumbo may be made 1 day ahead, cooled, uncovered, and chilled, covered.