Start with preparing all the vegetables for lentil ragu by chopping them finely before you start. Use food processor if you have one to speed up the process.
Heat the oil in a pan and add all your chopped veggies (onion, garlic, leek, carrots and celery). Let them sweat for good 5-8 minutes until softened but not coloured. Make sure you stir them frequently.
Rinse red lentils under the cold tap and once vegetables look nice and softened, add them to the pan and stir well.
Add tomato puree, chopped tomatoes, and stock. Bring to boil, cover and let it simmer for 15-20 minutes or until lentils are tender. Make sure you keep checking on them and stirring frequently to prevent them from sticking to the bottom of the pan.
When lentils are almost done add spinach and let it wilt in the sauce.
Once you are happy with tenderness of your lentils, season ragu to taste with salt and pepper and set aside.
To prepare white sauce, melt butter or vegan spread in a saucepan, add flour and mix it vigorously. Slowly start adding milk of your choice whisking constantly until you’ve used all of it and the sauce thickened nicely. Season to taste with salt, pepper and freshly grated nutmeg for vegetarian version and with nutritional yeast and mustard powder or English mustard for vegan..
To assemble your lasagne spread some ragu sauce at the bottom of your baking dishes as your first layer. Lay pasta sheets to cover and follow with some more ragu, white sauce and another layer of pasta. Repeat layers until you've used up all the sauces (you should finish with the layer of white sauce). My lasagne had 3 layers of pasta.
Top with sliced mozarella or grated cheddar for vegetarian version and bake in preheated oven 180°C/350F/Gas Mark 4 for 30-40 min until nicely browned and bubbling. You will know your lasagne is cooked if knife goes in easily through the pasta. For vegan lasagne feel free to sprinkle over your favourite vegan cheese or leave it as is with white sauce acting as your very top layer.
Serve with side salad or some green veg of your choice.
Freezing uncooked lasagne
Let your lasagne cool completely before freezing. Wrap it tightly in aluminium foil or baking paper first followed by aluminum foil for extra protection. Freeze for up to 3 months.
Cook from frozen at 180°C/350F/Gas Mark 4 for approximately 1 hr. Add your topping of choice for the last 15 minutes of baking. You can also defrost it in the fridge overnight first and follow the instructions for freshly cooked lasagne above.
Nutritional information is based on ingredients used for vegan option of the lasagne. The values are approximate, per serving (based on 8 servings) and should be treated as a guideline only.