Soak the TVP in hot water or vegetable broth for 30 minutes until rehydrated, then drain and squeeze out excess moisture.
Soak the cashews in hot water for 20 minutes, then drain.
Blanch the spinach by plunging leaves into boiling water for 1 minute, then drain and squeeze out excess water.
Remove the outermost cabbage leaf and peel off about a quarter head of larger leaves; blanch these leaves in hot water 5–8 minutes until soft, then chill and pat dry.
Heat a non-stick frying pan with a little olive oil over medium heat, sauté the chopped onion until glossy, then add the minced garlic and cook 1–2 minutes.
Add the rehydrated TVP to the pan and stir to combine, then add the chopped tomatoes, tomato puree, paprika, oregano, basil, salt, and pepper and simmer for about 5 minutes to make the marinara 'ground beef' layer.
In a blender, combine the soaked cashews, blanched spinach, 1 whole garlic clove, dairy-free milk, nutmeg (if using), nutritional yeast (if using), and salt and pepper; blend until smooth and creamy to make the spinach alfredo.
Preheat the oven to 400°F (200°C).
Assemble the lasagna in the oven-safe dish: spread a little of the TVP marinara on the bottom to prevent sticking, then layer blanched cabbage leaves, a layer of TVP marinara, a layer of spinach alfredo, and a sprinkle of dairy-free cheese; repeat layers until the dish is full (about 6 layer sets for a 9 x 7 x 3 inch dish).
Bake the assembled lasagna at 400°F (200°C) for 30 minutes until heated through and the top is lightly browned.
Remove from oven and let rest a few minutes before slicing and serving.
