While preparing the lasagna, soak your cashews in hot water for the cheese sauce if you do not have a high powered blender
Over medium high-heat, in a large and deep pan, sauté the onions and garlic with the herbes de provence and red pepper flakes in a couple splashes of vegetable broth. Sauté until the broth has evaporated and the onions are lightly cooked.
Add the chopped zucchini and mushrooms, sauté in a couple splashes of vegetable broth for 4 minutes until lightly cooked.
Rinse the quinoa (to remove the bitter aftertaste). Add the quinoa to the pan and sauté it with the vegetable for 2 minutes.
Break the lasagna sheets into thirds. Add the broken lasagna sheets to the pan. Cover with tomato sauce, chopped tomatoes and 1 cup of water. Stir lightly, cover and leave to sit for 15 minutes on medium-low heat.
After about 15 minutes, the quinoa and lasagna noodles should have absorbed most of the water. Stir and add more water if necessary (may use ⅓ cup of water). Cover and leave to cook until the quinoa is fully cooked.
Prepare the cheese sauce while the lasagna is simmering. Rinse the soaked cashews. Add the soaked cashews, nutritional yeast (amount you add will depend on how much you like nutritional yeast, 1-3 tbsps), lemon juice, sea salt, garlic and water to a blender. Blend for a couple minutes until smooth and creamy.
When the lasagna is ready (the quinoa fully cooked and water absorbed), add the cheese sauce, and cover for an addition minute. Stir in the sauce. Top with vegan parmesan and fresh basil.