Braised Tuna with Olive Relish and Spinach

Name: Braised Tuna with Olive Relish and Spinach
Ingredients: 1/4 cup (2 fl. oz./60 ml) vegetable broth; 5 Tbs. (3 fl. oz./ 80 ml) extra-virgin olive oil, plus more for drizzling; 1/4 cup (2 fl. oz./60 ml) dry white wine; 1/2 yellow onion, finely chopped; 3 bay leaves; Kosher salt and freshly ground pepper; 4 tuna fillets, each about 6 oz. (185 g); 1 cup (5 oz./155 g) pitted green olives; 1 cup (5 oz./155 g) pitted Kalamata olives; 2 garlic cloves, chopped; 1 tsp. red wine vinegar; Grated zest from 1 orange; 4 cups (4 oz./125 g) baby spinach