The single anchovy fillet lends umami depth to the dressing without giving it any sort of strong fishy flavor.
Serves 4 (serving size: about 5 shrimp, 2 1/2 cups salad, and 2 bread slices)
1. Combine the first 10 ingredients in a large bowl. Gradually add 1 tablespoon oil, stirring constantly with a whisk.
2. Heat a grill pan over medium-high heat. Coat pan with cooking spray. Combine shrimp and 2 teaspoons oil in a large bowl; toss to coat. Add shrimp to pan; cook 2 1/2 minutes on each side or until well marked and done. Remove shrimp from pan. Brush each side of bread slices with remaining 2 teaspoons oil. Add bread to pan; cook 1 minute on each side or until well marked.
3. Add lettuce to mayonnaise mixture; toss well. Divide lettuce mixture evenly among 4 bowls. Divide shrimp and bread evenly among servings.