Preheat the oven to 350?F.
Heat 2 tablespoons extra virgin olive oil in a large skillet or saucepan over high heat. Add the sausages and cook, stirring, until browned, 4 to 5 minutes. Add the onions, 3/4 teaspoon salt, and the black pepper. Cook, stirring occasionally, until the onions are just soft, about 4 minutes. Add the basil and garlic, and cook, stirring, for 2 minutes. Add the vodka and tomatoes, reduce the heat to medium-low, and simmer, uncovered, stirring occasionally, for 40 minutes. Add the Essence and heavy cream, stir to mix, and simmer for 5 minutes. Remove from the heat.
To cook the pasta, combine 4 quarts water, the olive oil, and the remaining teaspoon salt in a large pot over high heat. Bring to a boil, add the pasta, and cook until al dente, 12 to 14 minutes. Remove from the heat and drain well. Combine half of the ricotta cheese and half of the Parmigiano-Reggiano with the remaining 2 tablespoons extra virgin olive oil in a large mixing bowl. Add the pasta and toss to coat evenly. Add the sausage mixture and mix well. Add the remaining ricotta cheese and the remaining Parmigiano-Reggiano and mix well.
Transfer the mixture to a 9 x 13-inch baking dish. Sprinkle with the mozzarella cheese. Bake until bubbly and golden, about 45 minutes. Remove from the oven. Serve warm with crusty bread.
Makes 10 to 12 servings