If making homemade cashew ricotta, start by placing cashews in a small pot. Cover with water, bring to a boil, then simmer for 15 minutes. Drain and rinse then transfer to a food processor with fresh water, salt, and garlic powder. Blend until smooth and creamy, set aside.

Preheat oven to 375F. Bring a large pot of salted water to a boil. Add the pasta and cook al dente, according to package direction. Once cooked, reserve 1 cup of cooking water, then drain.

As the pasta cooks, warm about a tablespoon of olive oil over medium heat in a large skillet. Add mushrooms and cook for about 5 minutes, until they release their liquid. Add onion and garlic, saute for about 5 minutes, until onions are translucent and garlic is fragrant. Add spinach and cook for about 5 minutes, until wilted. Remove from heat.

Transfer the cooked pasta to the skillet with the mushroom sauce and stir well to combine. Add ¼ cup of reserved pasta water at a time to loosen the sauce.

Spread about half of the mixture in a 9x13 baking dish. Layer with half of the vegan ricotta cheese, then with remaining pasta and sauce. Top with remaining vegan ricotta.

Bake for 15-20 minutes, remove from oven and let cool for about 10 minutes. Sprinkle with fresh basil and serve warm.