Pan-Seared Sea Bass with ham hocks and savory red wine sauce from The Hog Island Book of Fish & Seafood: Culinary Treasures from Our Waters by John Ash

Ingredients

• 2 cups (220 g) chopped onions
• 2 cups (480 ml) beef stock or chicken stock
• 2 cups (480 ml) hearty red wine
• 2 pounds (910 g) smoked ham hocks, cut into 2-inch (5-cm) pieces
• 1 cup (140 g) peeled, chopped carrot
• 1 cup (100 g) chopped celery
• 3 ounces (85 g) cremini mushrooms, chopped (about 1 cup)
• 4 large cloves garlic, unpeeled
• 2 tablespoons olive oil
• 4 cups (960 ml) water
• 2 large bay leaves
• 2 whole cloves
• 1 teaspoon cracked black peppercorns
• 1 tablespoon balsamic vinegar
• 2 tablespoons unsalted butter, at room temperature
• 1 tablespoon unsalted butter
• 2 teaspoons olive oil
• Six 6-ounce (170-g) sea bass or grouper fillets, skin on
• Fine sea salt and freshly ground pepper