- Make the white layer: In a large saucepan over medium heat add oil and onion and cook, stirring frequently, for 2 minutes. Add the cauliflower, stock and mustard and bring to a boil with a lid on, then simmer for 10 minutes, unti cauliflower is tender. Stir in nutritional yeast (if using), let cool, then transfer to a blender and blend until smooth. Set aside.
- Make the green layer: add oil to a large frying pan over medium heat. Add courgette and saute for 3–4 minutes, stirring often.
- Make the red layer: heat a tablespoon of oil in a large pan over medium heat. Add onion and saute for 3 minutes. Add garlic, mushrooms and remaining oil and fry for 3–5 minutes, stirring often. Add dairy free lasagna sauce and lentils, bring to the boil, then simmer for 10 minutes, until thickened. Set aside.
- Lasagne: preheat the oven to 180°C. In a large ovenproof dish add a drizzle of oil, then a layer of lasagne sheets. Add red sauce and season with salt and pepper, then another layer of lasagne sheets. Add courgettes, pesto, kale, basil, and season with salt and pepper, then layer with lasagne sheets. Pour in the white sauce, season with salt and pepper, sprinkle with cheese, then cover with thinly sliced courgette.
- Bake in the oven for 30–35 minutes, until golden and cooked through.
- For those without dietary preferences, you can use regular Diamond lasagne sheets.