Canadian Bacon and Mozzarella Penne

In a small bowl, combine the mozzarella, garlic, 1 1/2 tablespoons of the oil, 1/4 teaspoon of the salt, 1/4 teaspoon red-pepper flakes, and the parsley. In a large saucepan, heat the remaining 1 tablespoon oil over moderately low heat. Cook the onion, stirring occasionally, until translucent, about 5 minutes. Add the tomatoes, water, the remaining 1/2 teaspoon salt, and a pinch of red- pepper flakes. Reduce the heat and simmer, covered, for 15 minutes. In a large pot of boiling, salted water, cook the pasta until just done, about 13 minutes. Reserve 1/4 cup of the pasta-cooking water. Drain. Toss the pasta with the tomato sauce, mozzarella mixture, and Canadian bacon. If the sauce seems too thick, add some of the reserved pasta-cooking water.