Cook a large pot of salted water to a rolling boil. Add the jumbo pasta shells and cook for 9-11 minutes until al dente, stirring occasionally. Drain and toss with olive oil to prevent sticking.

In a food processor, blend drained extra-firm tofu with nutritional yeast, olive oil, and lemon juice until smooth yet slightly chunky. Season with salt and pepper.

In a mixing bowl, fold canned pumpkin purée and freshly grated nutmeg into the tofu ricotta. Adjust seasoning to taste.

Sauté chopped onions and minced garlic in olive oil over medium heat until soft, about 3-4 minutes. Gradually whisk in flour, then add lite coconut milk. Whisk until the sauce thickens, about 5-7 minutes.

Spread a thin layer of béchamel sauce in a greased baking dish. Stuff pasta shells with pumpkin filling and arrange them open side up. Drizzle remaining sauce over the shells and add fresh sage. Bake at 350°F for 25 minutes.