If using regular lasagna noodles, cook them in salted boiling water until al dente but not mushy.
Make the meat sauce by heating the oil in a large saucepan. Add the onions and garlic. Saute, until they soften, about five minutes. Add the "meat" crumbles and saute for a couple of minutes. Add the tomato paste and mix in.
Put the plum tomatoes in a bowl and squish them to break with your fingers. Add to the saucepan along with 3 cups of vegetable stock if using no-boil noodles, and 2 cups of stock if using regular noodles that have been cooked.
Stir well, bring to a boil, add the oregano, red pepper flakes, salt and ground black pepper to taste. Stir and let the sauce cook for about 15 minutes or until it turns a bright red. Turn off heat and check seasoning. Set aside.
Make the ricotta, by placing the cashews in a food processor with all ingredients except the parsley. Process for a couple of minutes until fairly smooth. Mix in the parsley and pulse until it's mixed into the rest of the ricotta. Set aside.
Preheat oven to 400 degrees Fahrenheit.
Assemble the lasagna by spraying a 12 X 9 inch lasagna pan with cooking spray or oil. Ladle out a small amount of sauce into the pan and spread.
Layer on four sheets of the noodles into the bottom of the pan. If using no-boil noodles, which are smaller than regular noodles, you might need to layer on five noodles vertically and one more horizontally.
Layer on one-fourth of the meat sauce over the lasagna noodles.
Layer on one-fourth of the cashew parmesan.
Layer on one-fourth of the vegan mozzarella.
Layer on one-fourth of the vegan ricotta.
Repeat until you have built up three layers of the meat sauce and the cheeses. Over the fourth and final layer, layer the remaining meat sauce, parm and mozzarella.
Cover tight with aluminum foil, place the lasagna pan on a rimmed baking sheet, and bake in the preheated oven for 30 minutes. After 30 minutes, remove the aluminum foil and bake another 30 minutes until bubbly and hot.
Let the lasagna stand at least 15 minutes to firm up, then cut and serve.