- Preheat the oven to 180°C/gas 4. Blend together the tomatoes, tomato puree, garlic and oregano to make a tomato sauce, then set aside.
- Heat the oil in a pan and add the onion. Cook for 2–3 minutes, add the red pepper and cook a further 2–3 minutes. Add the mushrooms, cook for 2 minutes then gradually stir in the flour to coat the vegetables.
- Gradually, stir in the milk until it starts to thicken, add the spinach and stir for 1 minute then stir in the cream cheese, mustard and black pepper.
- To an ovenproof dish add a little of the tomato sauce then top with a layer of lasagne. Now add a layer of the mushroom, spinach and cheese mix and repeat until you end with a layer of tomato sauce then top with the thinly sliced tomatoes.
- Sprinkle with Cheddar and bake for 30–35 minutes. Scatter with fresh basil to serve.
- For a gluten-free version or if you’re watching your carb intake, use 3-4 sliced aubergines in place of the lasagne sheets and use gluten-free flour in the sauce.
- Freezing instructions: Suitable for freezing once cooked. Defrost in the fridge or microwave and reheat until piping-hot throughout.