Heat 2 Tbps olive oil and the mushrooms in a skiller over medium heat until the mushrooms become soft. Add the ground turkey and cook until it's brown all the way through. Pour the marinara sauce into the skillet and mix to coat the turkey. Set aside while you prepare the ricotta.
Place the softened cashews in a food processor or blender and blend until chopped up. Add the tofu, olive oil, almond milk, garlic, sea salt, and oregano to the container and blend until a thick and creamy mixture forms. Add the spinach and pulse until it's chopped up. Be sure not to blend for too long or the mixture will turn green.
To assemble, spoon a little extra marinara sauce into the bottom of an 8 X 8 baking dish. Then add three lasagna sheets followed by a layer of ricotta cheese (you should use about a cup). Spoon half of the turkey mixture over the ricotta. Spread it out to the edges of the dish. Repeat with another layer of lasagna noodles, ricotta, and turkey mixture. Sprinkle the dairy free mozzarella over top, if desired, and bake in the oven for 40 - 50 minutes until the edges begin to get dark and crispy.
Allow the lasagna to set for about 30 minutes before slicing it into squares with a sharp knife. Use a serving utensil or a spatula to remove each slice. Garnish with parsley and enjoy!