Substituting cooked chicken for the lobster also yields excellent results.

　　

Ingredients

Serves 6

　　2 pounds small white boiling potatoes (about 2 inches in diameter)

　　1 medium onion

　　1 firm-ripe California avocado

　　1 bunch fresh dill

　　3 cups cooked lobster meat (about 1 pound)

　　3/4 cup mayonnaise

　　1/2 cup sour cream

　　2 tablespoons drained bottled horseradish, or to taste

　　1 tablespoon red-wine vinegar

　　1 bunch watercress

　　

Step 1

In a 5-quart kettle cover potatoes with salted cold water by 2 inches and simmer until just tender, 15 to 20 minutes. Drain potatoes in a colander and, while still warm, cut into quarters. Transfer potatoes to a large bowl and cool.

　　

Step 2

Finely chop onion. Halve, pit, and peel avocado and cut into 1/2-inch pieces. Chop enough dill leaves to measure 1/2 cup. Cut lobster into 1/2-inch pieces and add to potatoes with onion, avocado, and dill.

　　

Step 3

In a small bowl whisk together mayonnaise, sour cream, horseradish, vinegar, and salt and pepper to taste and pour over salad. Gently toss salad until combined well and season with salt and pepper. Chill salad, covered, at least 1 hour and up to 1 day.