Heat 2 tbsp olive oil in a frying pan. Fry the onions until soft. Then add the garlic and the chopped mushrooms, and season with salt and pepper.
Sauté until the mushrooms are softening. Add the shredded spinach and continue to cook for a couple of minutes until it wilts. Add 1 tin of chopped tomatoes and simmer for five minutes.
Drain the cashews and blend with 115ml water and 1 tbsp nutritional yeast until you have a creamy sauce.
Season with salt and pepper, then add half to the mushroom mixture in the pan and cook for 1 min. Set aside.
Heat up 1 tbsp olive oil in a separate pan. Add the chopped tomatoes and tomato puree and stir well. Add the oregano and cook until the sauce thickens. Season with salt and pepper. Add the cubes of vegan cheese. Stir well, remove from the heat and set aside.
Pre-heat the oven to 180°C (fan)/200°C/gas mark 6.
Boil a large saucepan of water and prepare a large bowl of iced water. Cook the lasagne sheets until al dente (around 10 minutes), then drain and drop into the iced water.
Just before the lasagne is cooked spread some of the tomato sauce onto the bottom of a greased baking dish.
Remove the sheets from the iced water, separate and spread out on kitchen towel. Pay dry then transfer to a chopping board and cut in half, lengthways so you have two long strips.
Spread some of the mushroom mixture onto the sheets, rolling up from the short end. Cut in half with a sharp knife and place in the baking dish with the cut side facing up.
Fill the gaps between each roll with the remaining tomato sauce and cashew cheese sauce and sprinkle over the grated cheese.
Bake for 20 minutes until the sauce is bubbling and the cheese has melted.