Bring a large pot of salted water to a boil. Cook the jumbo pasta shells until al dente, about 8-10 minutes. Drain and toss with olive oil. Set aside.

In a food processor, blend drained tofu, nutritional yeast, garlic powder, onion powder, salt, pepper, olive oil, lemon zest, lemon juice, and crushed red pepper until chunky ricotta-like consistency.

Fold the tofu ricotta with canned pumpkin purée, freshly grated nutmeg, and vegan parmesan in a mixing bowl until creamy and evenly combined.

Heat olive oil in a medium saucepan, sauté chopped onions until soft, then add minced garlic. Add flour and whisk in coconut milk to thicken.

Spread garlic béchamel sauce on the bottom of a baking dish. Stuff each shell with pumpkin filling and arrange in the dish. Pour remaining sauce over shells and sprinkle with sage.

Bake at 350°F (175°C) for 22-25 minutes until bubbly and golden. Let cool before serving.