To make the crispy sage, add the olive oil to a pan and heat. Add the sage and let crisp up until fragrant. Remove from the pan and set aside.
In a large shallow pan or Dutch oven heat olive oil over medium-high heat. Add garlic and onion. Cook until soft (being careful not to burn the garlic).
Add the tomato paste, and cook until it appears caramelized. Then, add the vodka and let it cook off.
Meanwhile, cook ravioli until al dente. Reserve 1 cup of pasta water. Pour the pumpkin puree into the tomato paste mixture and combine until smooth. Then, lower the heat to medium, add the heavy cream, and mix again. Sprinkle the crushed red pepper and season with salt and pepper.
Over low heat, add a 1/2 cup reserved pasta water, the butter, freshly grated nutmeg, and Parmigiano Reggiano. Add salt to taste, and continue adding pasta water as needed until the sauce is smooth and liquid-y, but not soupy.
Add the ravioli to the sauce and gently fold to coat to maintain their structure.
To serve, top with a sprinkling of Parmigiano Reggiano and the crispy sage! Enjoy!