Boil the pasta al-dente for ~6 minutes. It just needs to be soft.
Preheat the oven to 200C.
Make the sauce:
Heat the olive oil in a skillet over medium heat. When hot, add the sliced onion, minced garlic and saute for about 3 minutes, until soft. Add crushed tomatoes, basil leaves, salt, and pepper and cook for 7 more minutes, stirring occasionally. When the sauce is ready, set aside.
For the pasta stuffing:
Heat the oil in a skillet, over medium heat. When hot, add the onions and saute for 3 minutes, add spinach and cook until wilted for about 5 minutes. Set aside.
In a food processor, add the soaked raw cashews, crumbled tofu, lemon juice and nutritional yeast. Blend until smooth.
Add the cooked spinach and pulse 2-3 times. Scoop a tablespoon of stuffing in each cooked pasta tube.
Place the stuffed pasta in a baking dish, in a single layer, pour over the tomato sauce and bake it for about 30 minutes.
Top with some shredded vegan cheese and serve.