Salmon with Lentils

INGREDIENTS

• 4 (8-ounce) center-cut salmon fillets, skin removed
• 6 carrots, unpeeled and halved
• 1 1⁄2 cups Homemade Chicken Stock, recipe follows, or good canned broth
• 1 1⁄2 cups chopped carrots (3 carrots)
• 2 tablespoons tomato paste
• 3⁄4 teaspoon freshly ground black pepper
• 4 parsnips, unpeeled and cut in 1/2, optional
• 2 tablespoons good red wine vinegar
• 2 tablespoons kosher salt
• 1 teaspoon fresh thyme leaves
• 15 sprigs fresh thyme
• 3 large onions, unpeeled and quartered
• 1⁄2 pound French green lentils (lentilles du Puy)
• 2 teaspoons whole black peppercorns
• 1 tablespoon minced fresh garlic
• 20 sprigs fresh flat-leaf parsley
• 4 celery stalks with leaves, cut in thirds
• 2 teaspoons kosher salt
• 20 sprigs fresh dill
• 1 head garlic, unpeeled and cut in 1/2 crosswise
• 2 cups chopped yellow onions
• 3 (5-pound) chickens
• 1⁄4 cup good olive oil, plus extra for salmon
• 2 cups chopped leeks, white and light green parts only
• 1 1⁄2 cups chopped celery (4 stalks)