• Bring a large pot of salted water to a boil. Cook the shells according to package directions, then drain and rinse gently with cold water. Set aside.

Make the stuffed shells

• Heat a medium skillet over medium heat. Add the olive oil, spinach, and one minced garlic clove and cook until the spinach is just tender and wilted, about 5 minutes. Season with a pinch of salt and set aside to cool, then roughly chop.
• In a large bowl, mix together the ricotta, parmesan cheese, 1/4 teaspoon salt, red pepper flakes, nutmeg, and chopped cooked spinach. Season to taste and set aside.

Make the pumpkin sauce

• Add the cashews, cauliflower and 2 cups water in a medium saucepan and bring to a boil. Reduce heat to medium and cook for 10 minutes until cashews and cauliflower are softened—strain and place in the base of a blender.
• In the same skillet you used to cook the spinach, heat the 1/4 cup of olive oil over medium heat and add the garlic. Cook until just fragrant, taking care not to burn, about 30-60 seconds. Add all the contents to the same blender along with the pumpkin puree, salt, broth or water, and lemon juice. Puree until very creamy and smooth.
• Preheat the oven to 350 degrees F.

Assemble

• Place a generous layer of the pumpkin sauce in the bottom of a 9 x 13" roasting pan. Stuff the cooked shells with the spinach mixture, taking care not to overfill and place the stuffed shells into the pumpkin bechamel. Cover with the rest of the pumpkin sauce and sprinkle with extra parmesan cheese, if desired. Cover with foil and bake for 20 minutes until the sauce is hot and the cheese is melted, remove the foil and cook another 5 minutes, then remove and serve.