In a large pot, bring 5 quarts salted water to a boil. Add the pasta and cook until al dente, or as directed. Strain cooked pasta while reserving 1 cup of the cooking water.
Meanwhile, in a large skillet, warm two tablespoons olive oil over medium-low heat. Add the shallot (or onion) and cook for about 3 minutes, until translucent and fragrant. Add the garlic and continue to cook for another 2 minutes. Remove from heat and set aside.
In a high speed blender, add the pumpkin puree, drained soaked cashews, cooked shallot and garlic, reserved pasta water, nutritional yeast, vinegar, paprika, sage, salt & pepper. Blend on high until a smooth creamy sauce forms. If sauce is too thick, add more water to thin. Taste test to see if you prefer more bouillon, vinegar, paprika, sage or salt and add accordingly.
Next, add the pasta to the pot and pour pumpkin cheese sauce over top. Stir until evenly coated. Warm over medium-low heat and cook until heated through. Add more salt to taste, if desired. Serve warm and enjoy!