- 6 long parsley sprigs, divided
- 1 3/4 cups reduced-sodium chicken broth
- 1 large garlic clove, minced
- 2 teaspoon unflavored gelatin (from 1 envelope)
- 3 tablespoons water
- 1 (3/4-pound) piece baked ham, cut into 1/2-inch cubes (2 cups)
- 1/2 cup mayonnaise
- 2 tablespoons Dijon mustard
- 2 tablespoons white-wine vinegar
- 2 celery ribs, finely chopped (1 cup)
- 1/4 cup chopped cornichons or sour gherkins
- 1 pound boiled potatoes, peeled and cut into 1/2-inch cubes (2 1/2 cups)
- 1 (10-ounce) box frozen baby peas, thawed
- 2 teaspoons finely chopped marjoram
- 3 tablespoons extra-virgin olive oil
- Equipment: 4 (16-ounce) wide jars or containers with lids
- Garnish: celery leaves
- Chop enough parsley leaves to measure 1 tablespoon; reserve. Chop remaining leaves and stems and simmer with broth and garlic in a small saucepan, covered, 5 minutes.
- Meanwhile, sprinkle gelatin over water in a medium bowl and let soften 1 minute. Strain broth through a fine-mesh sieve into bowl with gelatin and stir to dissolve. Season with salt and pepper. Set bowl in an ice bath and cool to room temperature, stirring.
- Toss ham with reserved parsley and divide among jars. Pour gelatin on top and chill until set, at least 1 hour.
- Whisk together mayonnaise, mustard, vinegar, 1/4 teaspoon salt, and 1/4 teaspoon pepper in a large bowl. Stir in celery, cornichons, and potatoes.
- Pulse peas with marjoram, oil, 1/2 teaspoon pepper, and 1/4 teaspoon salt in a food processor to a coarse mash.
- Layer peas, then potato salad, over ham.