How to make it
Heat the oven to 200C/180C fan/gas 6. Put the prepared vegetables on a large baking tray, drizzle over 2 Tbsp oil and toss together, season with salt and pepper. Roast for 30 minutes.
Meanwhile, heat the rest of the oil in a frying pan, add the mushrooms and stir fry for 3-4 minutes until tender. Add Oyster Sauce and cook a further minute.
When the vegetables come out of the oven, add mushrooms, toss together then spoon half into a 20x30cm baking dish. Spoon over half of the passatta and arrange a layer of lasagne sheets on top. Repeat the layers.
Squeeze out as much water from the spinach as possible, put into a bowl and add the egg, Oyster Sauce, ricotta and parmesan, and season with black pepper, mix together then spoon evenly on top of the lasagne.
Return the dish to the oven and bake at 190C/170C fan/gas 5 for 30 minutes until golden, cover with foil if it browns too quickly.