Roasted Potatoes and Haddock Puttanesca

Name: Roasted Potatoes and Haddock Puttanesca
Ingredients: 3 1/2 tablespoons olive oil, divided; 4 garlic cloves, sliced; 4 anchovy fillets packed in oil, drained; 1/4 teaspoon crushed red pepper flakes; 1 28-ounce can whole peeled tomatoes and their juices, coarsely puréed; 1/4 cup halved, pitted oil-cured black olives; 1/2 teaspoon kosher salt plus more; 1/4 teaspoon freshly ground black pepper plus more; 1 pound fingerling potatoes, halved; 2 large shallots, peeled, leaving root end intact, quartered; 8 ounces haddock or halibut fillets, cut into 1 1/2 cubes; 1/4 cup halved caper berries or 1 tablespoon drained capers, rinsed; 1 tablespoon chopped flat-leaf parsley