To make the sauce: Heat the oil in a Dutch oven or flameproof casserole over medium heat. Add the onion and cook, stirring often, until golden, about 5 minutes. Stir in the garlic and cook until fragrant, about 1 minute. Add the wine and bring to a boil. Stir in the tomatoes with their puree, 1 cup water, tomato paste, tomato sauce, oregano, and hot pepper flakes. Bring to a boil, and reduce the heat to low. Simmer uncovered, stirring occasionally, until slightly thickened, about 1 hour.