Lamb Shanks in Red Wine With Creamy Eggplant

Name: Lamb Shanks in Red Wine With Creamy Eggplant
Ingredients: 1⁄4 cup olive oil; 6 lamb shanks (about 4 1/2 lbs.); Kosher salt and freshly ground black pepper; 1⁄2 tsp. whole black peppercorns; 3 stalks celery, minced; 2 cloves garlic, minced; 2 sprigs rosemary; 2 sprigs thyme; 1 bay leaf; 1 medium yellow onion; 5 tbsp. tomato paste; 2 cups red wine; 1 (1-lb.) eggplant; 2 tbsp. unsalted butter; 3 tbsp. all-purpose flour; 1⁄2 cup whole milk; 1⁄4 cup grated Gruyère; Freshly grated nutmeg