Catalan-Style Shrimp in Chocolate Sauce

Peel and devein shrimp, reserving shrimp shells. Place shrimp in a large bowl. Add 1 tablespoon salt to shrimp, and rub into shrimp. Rinse, drain, and pat shrimp dry. Cover and refrigerate until ready to use.

Heat 1 tablespoon oil in a medium saucepan over medium until barely rippling, about 1 minute. Add onion; cook, stirring often, until soft, fragrant, and beginning to turn golden, 4 to 5 minutes. Stir in tomato, celery, ham, fennel seeds, bay leaf, thyme, and reserved shrimp shells. Cook, stirring often, until mixture is aromatic, about 1 minute. Stir in 2 1/2 cups water; bring to a gentle boil over medium. Reduce heat to medium-low; cook, undisturbed, until liquid has reduced by about one-third, about 30 minutes. Remove from heat. Pour through a fine wire-mesh strainer into a large heatproof measuring cup or bowl, pressing on solids with a spoon to yield about 1 1/2 cups broth; discard solids. Stir in 3/4 teaspoon salt.

While shrimp broth cooks, stir together almonds and 1/2 teaspoon oil in a large skillet. Cook over medium, stirring often, until many pieces are pale golden, about 3 minutes. Remove from heat; let cool completely (almonds will darken as they cool), about 20 minutes.

Transfer cooled almonds to a blender; process until almonds form a fine texture, 10 to 15 seconds. Add chocolate, garlic, and half of the shrimp broth. Secure lid on blender, and remove center piece to allow steam to escape. Place a clean towel over opening. Process until mostly smooth (some bits of chocolate will remain), about 15 seconds. Add remaining broth to mixture in blender; process until liquid is very smooth and turns the color of milk chocolate, about 30 seconds. Set aside, covered, at room temperature until ready to use. (Alternatively, pound almonds using a mortar and pestle [omitting the 1/2 teaspoon oil], and work into the chocolate and garlic to yield a paste. Stir in 1/2 cup broth until well combined, and scrape mixture into remaining broth in measuring cup. For a smooth finish, pour sauce through a fine wire-mesh strainer.)

Return large skillet to heat over medium. Add remaining 1 1/2 tablespoons oil to skillet, and heat until barely rippling, about 1 minute. Add half of the peeled shrimp. Sprinkle with 1/8 teaspoon salt and 1/8 teaspoon pepper; cook, stirring often, until shrimp just start to curl and turn opaque, 1 to 2 minutes. Transfer cooked shrimp to a plate. Repeat process with remaining shrimp, remaining 1/8 teaspoon salt, and remaining 1/8 teaspoon pepper. Do not wipe skillet clean.

Add chocolate sauce and parsley to large skillet. Cook over medium, stirring often, until sauce is silky and thick enough to coat the back of a spoon, 4 to 5 minutes. Reduce heat to medium-low; return shrimp to skillet, and cook, stirring often, until warmed through, 1 to 2 minutes. Remove from heat. Add more salt to taste, if desired. Transfer mixture to 1 large, shallow bowl or 4 individual bowls or dishes, serving shrimp over white rice, if desired. Sauce will thicken as it sits. If needed, stir in water, 1 tablespoon at a time, to reach desired consistency.