I make this dish on a fairly regular basis, such is the gusto with which Mr. F devours it. It has also proved successful with my in-laws who have exacting standards. I therefore commend it to you. Chargrilling the aubergines gives the dish a wonderful smoky flavour and silky texture.
One note of caution should be sounded. Lentils absorb a lot of flavour and seasoning. I would therefore entreat you to check the seasoning for the lentil sauce and make sure that it is salty enough.
The following recipe makes enough for 4 to 6 people (a baking dish that measures about 25cm by 25cm). Any left over lentil ragu is good over pasta or with some soft cheesy polenta.
Two large aubergines, green tops removed and then sliced lengthways into slices about 1cm thick
Two balls of buffalo mozzarella, sliced
Large bunch of basil
50g of freshly grated Parmesan
25g of breadcrumbs (optional)
1 box of lasagne sheets (wholewheat if you absolutely must, but really, you shouldn't)
For the lentil ragu:
Two tins of small green or brown lentils (or you can use Puy or Castellucio lentils which you have cooked from dried)
Two tins of chopped Italian tomatoes
One large onion, finely chopped
Two large cloves of garlic, finely chopped
Knob of butter
EV olive oil
Pinch of caster/granulated sugar
Salt and pepper
For the bechamel sauce:
500ml of milk (whole milk or semi-skimmed)
100g of butter
100g of flour
One bay leaf
Half an onion
Salt and pepper
Start with the lentil ragu as it will need to simmer for about an hour. Fry the onion in the olive oil until it is soft and translucent, but not browned, about 10 minutes. Add the garlic and cook for a few seconds until you can smell it wafting out of the pan. Add the tomatoes, seasoning, sugar and oregano. Fill both of the empty tomato tins with water and add that to the pot. Bring the sauce to the boil. Mix in the lentils and the butter, return to the boil and then reduce the heat. Simmer the ragu uncovered for about an hour, or until it is thick. You do not want to cook away all of the liquid as some will be needed to cook the dried pasta. Tomato puree and dried chilli flakes can be added to the ragu to enhance the flavour if you wish. Check the seasoning and add more salt if necessary.
Whilst the lentils are cooking, chargrill the aubergines (which you will have brushed with EV olive oil on both sides) until they are soft and darkly ridged. If you do not have a grill pan then you should make a mental note to buy one at your earliest convenience. In the meantime, you can grill the aubergines until they are golden brown on each side. You will also need to brush the aubergine slices with olive oil before you do so. Once the slices are cooked, place them on a plate and sprinkle with salt.
To make the bechamel, heat the milk with the onion and bay leaf until just below boiling point. Leave the milk to infuse for about 10 minutes and then discard the bay leaf and onion. In another pan, melt the butter, and when it is foaming, add the flour. Cook the mixture for about a minute and then gradually add the bay-scented milk. I use a small whisk to incorporate the milk into the butter/flour which seems to protect against the sauce becoming lumpy. When all the milk has been added, turn the sauce down to simmer for about 15 to 20 minutes. Season well.
When you are ready to assemble the lasagne, preheat the oven to 180 degrees. I usually layer my lasagne as follows:
Thin layer of bechamel sauce
Layer of basil leaves
Bake the lasagne for about 45 minutes, or until it is golden brown and bubbling and the pasta is cooked. I let it cool for about 15 minutes before serving. This dish is good with a green salad and buttery garlic bread.