Sheet Pan Shrimp Puttanesca

Name: Sheet Pan Shrimp Puttanesca
Ingredients: 1 red onion, cut into wedges; 3 cups sourdough bread, cut into 1-inch cubes; 1 pint (2 cups) cherry tomatoes; 1/2 cup pitted Niçoise olives; Kosher salt and freshly ground black pepper; 4 tablespoons olive oil; 2 pounds jumbo (U15) shrimp, peeled and deveined and tails removed; 2 tablespoons red wine vinegar; 1 anchovy, minced; 1 tablespoon capers, drained; 1/3 cup fresh parsley leaves, plus 2 tablespoons, chopped; Parmesan shavings, for garnish