Combine pumpkin puree with the vegetable broth in a blender and blend until well pureed, pour over the rice and let stand for 10 minutes, stirring occasionally. Drain the rice, keeping the broth mixture separately, and let stand for 10 minutes.
Heat olive oil in a pot over medium high heat; add the sage and fry briefly, about 15 seconds. Add the drained rice followed by the onion and garlic, stir to toast rice, about 1 minute. Add the previously strained liquid, salt, and black pepper and bring to a boil, reduce to a very low simmer. Cover pot and simmer until all the liquid has been absorbed, about 15 minutes.
Add the parmesan cheese and stir until cheese has fully melted. Cover and simmer for 5 more minutes before serving.
Notes
Storage: Store any leftovers in an airtight container. They will last about 2-3 days in the fridge, but the consistency is best on the first day. Re-heat in the microwave with a splash of vegetable broth and a dab of butter and/or parmesan cheese.