Cook the pasta in salted boiling water until al dente, about 8-10 minutes. Drain, drizzle with olive oil, and set aside to cool.

Blend tofu, nutritional yeast, garlic powder, onion powder, kosher salt, black pepper, olive oil, lemon zest, juice, and red pepper flakes in a food processor until slightly chunky.

Mix tofu ricotta with pumpkin purée and nutmeg in a bowl. Adjust seasoning and fill each shell with the mixture.

Heat olive oil in a frying pan, sauté onion for 5-7 minutes, then add minced garlic and cook for another 1-2 minutes.

Whisk in flour for 1 minute, slowly add coconut milk, and cook until thickened, about 2 minutes.

Blend the béchamel sauce until smooth, adjusting with salt and pepper as needed.

Pour béchamel sauce into a baking dish, arrange stuffed shells, drizzle with remaining sauce, and garnish with sage.

Bake at 350°F (175°C) for 22-25 minutes until golden and bubbling. Allow to cool slightly before serving.