Cook the Pasta: Begin by bringing a large pot of salted water to a rolling boil. Add the jumbo pasta shells and cook until al dente, about 9-11 minutes. Drain the shells, then drizzle with olive oil to prevent sticking. Set aside.

Prepare Tofu Ricotta: In a blender, combine drained extra-firm tofu, nutritional yeast, garlic powder, olive oil, lemon zest, and lemon juice. Blend until creamy. This tofu ricotta will provide a base for your filling.

Make Pumpkin Filling: Combine the prepared tofu ricotta with the canned pumpkin purée, freshly grated nutmeg, and vegan parmesan cheese in a mixing bowl. Stir until incorporated and season with salt and pepper.

Prepare Garlic Béchamel Sauce: In a saucepan, heat olive oil and sauté the chopped onion until translucent, about 3-4 minutes. Add minced garlic and stir for 1 minute. Whisk in flour, cooking for a minute, then gradually pour in coconut milk, whisking until thick.

Assemble the Dish: Spread a layer of béchamel sauce on the bottom of a baking dish. Stuff each shell with the pumpkin filling and place them in the dish. Pour remaining sauce over the top and sprinkle with fresh sage leaves.

Bake the Stuffed Shells: Preheat your oven to 350°F (175°C). Cover the dish with foil and bake for 22-25 minutes. Remove foil for the last few minutes to achieve a golden crust.