Preheat the oven to 400 degrees. In a large saucepan, heat 1 tablespoon of the olive oil. Add the garlic and cook over moderate heat, stirring, until lightly browned, about 1 minute. Add the sausage and cook, breaking up the meat, until browned, about 8 minutes. Add the tomato puree, water, sugar, bay leaf and fennel. Season with salt and pepper and bring to a boil. Simmer over low heat until thickened, about 30 minutes. Remove the garlic, mash it to a paste and stir it back into the sauce; discard the bay leaf.

Meanwhile, cook the penne in a large pot of boiling salted water until al dente. Drain the pasta and return it to the pot. Stir in the remaining 2 tablespoons of olive oil. Using a slotted spoon, add the cooked sausage to the pasta, then add 1 cup of the tomato sauce and toss to coat the penne.

Spoon the pasta into a 9-by-13-inch baking dish. Pour the remaining tomato sauce over the pasta and dollop large spoonfuls of the Creamy Ricotta on top. Gently fold some of the ricotta into the pasta; don't overmix -- you should have pockets of ricotta. Scatter the mozzarella on top and sprinkle with the Parmigiano-Reggiano. Bake the pasta for about 45 minutes, or until bubbling and golden on top. Let rest for 20 minutes before serving.

The baked penne can be refrigerated, covered, overnight. Rewarm before serving.