Add the cashews to a glass jar or bowl and cover with boiling water. Set aside to soften for 30 min.
In the meantime, mix together the panko, rosemary, and salt then heat the oil over medium-low heat in a skillet. Add the panko mix and toast, stirring often until golden, 3 to 5 mins. Set aside.
Boil a pot of salted water and cook the rigatoni until al dente. Drain and rinse with cold water. Return to the pot, off of heat.
While the pasta cooks, heat the oil in a skillet over medium. Add the shallot and cook until translucent, stirring often, 2 to 3 min. Add the garlic and cook for another minute, then remove.
Add the soaked cashews to a blender or food processor along with the onion and garlic, broth, pumpkin puree, nutritional yeast, salt, pepper, and sage. Blend until completely smooth. If needed, add water or additional broth 2 tablespoons at time to thin.
Add the sauce to the pasta and mix to coat. Serve immediately for best results with a sprinkle of breadcrumbs on top.
