I originally found this recipe, by Nigel Slater, in the first of the Kitchen Diaries, one of my first serious cook books. I’ve made it many times since and this is my version, which I’ve amended over the years.
It makes a great supper if you need to cook in advance. The whole dish is a bit of a labour of love, in that it takes time and use all manner of dishes and pans, but you can make the components in advance and then put them together later, and the whole dish can be frozen in advance as well, so in that way it’s less trouble than stressing over a risotto while everyone is sitting waiting to eat. It is worth making the bechamel yourself if you have time, but if you’d rather buy it ready-made, go for it. Apologies for no image. I’ll try to add one next time I make it. This serves 6.
Mushroom lasagne with pesto
For the filling
800g fresh mushrooms (white mushrooms are fine, but if you have a handful of wild mushrooms this will make it all the more interesting), thinly sliced.
1 large onion, finely chopped
2 cloves of garlic, peeled and crushed
125ml white wine or vermouth (if you have a bottle open)
200ml double cream
20g dried porcini or other mixed wild mushrooms
20g parsley (flat leafed or curly) chopped (optional)
For the pesto
20g fresh basil
1 clove garlic, peeled and crushed
50g mature cheddar cheese or parmesan, grated
50g flaked almonds or pine nuts
salt and pepper to taste
around 2 tbsp extra virgin olive oil
For the bechamel
700ml whole milk
1 bay leaf
pinch black peppercorns
1 small onion, halved
1 celery stalk, roughly chopped (if you have one)
75g unsalted butter
60g plain flour
To put together
Around six sheets of lasagne (dried is fine)
An extra grating of parmesan or mature cheddar cheese
Add 150ml boiling water to the dried mushrooms and set aside to soak.
Heat 25g butter in a large pan, add the onions and cook for around 6 minutes until starting to turn transparent.
Add the garlic and fresh mushrooms. Raise the heat to high and cook, stirring until the mushrooms release their liquid and this bubbles off. Add the dried mushrooms and their liquid, again reduce down until the liquid has almost all evaporated. Do the same with the white wine (if using) and then add the double cream.
At this stage lower the heat slightly and let the mixture bubble away gently until it thickens and changes to a slightly richer colour. Add the chopped parsley if using. Once the mixture is thick, but before it has all evaporated, remove from the heat. Season with salt and pepper and set aside.
Make a bechamel sauce by cooking the butter and flour in a small pan over a low heat for 2-3 minutes. Strain the infused milk and add, in 4 or 5 batches, whisking to incorporate each time. Bring to a simmer and cook for 5-7 minutes, whisking regularly, until thickened. Cover and set aside.
Just place the basil leaves, cheese and nuts with the garlic in a high sided bowl and blend with just enough oil to bind it. You don’t want too much oil in this as otherwise the top of the lasagna will be floating in oil when baked. Set aside.
All these stages can be made a day or so in advance and kept in the fridge.
To put together
Using a large lasagne dish layer first the mushroom mixture and then place sheets of lasagne (I find each layer takes 3) followed by another layer of filling, ending with a layer of lasagne.
Now spread a layer of pesto over the lasagne sheets, and then cover this with the bechamel. You may not need all the bechamel. (If it’s started to get lumpy, don’t panic. Just press it through a sieve. No one will notice).
Top it all with a further grate of cheese and then either bake in the oven or set aside in the freezer until needed.
Cooked from room temparature it will take around 40 minutes on a medium over (180C),and you’re looking for the top to be golden brown and bubbling away around the edges with some vigour. If you are cooking from chilled and especially if from frozen allow substantially longer.
When done, remove from the oven and allow to stand for a few minutes before serving. This goes very well with a mustardy mixed salad.