Bechamel isn't exactly a cutting edge sauce. You're unlikely to find it on the menu at el Bulli, but it should be an invaluable part of every home cook's repertoire. Your lasagne would look pretty sick without for a start. Here, it unifies three dispirate vegetables into a coherent dish that you can use to accompany any roast or grilled meat, or even fish. Serve it with homemade bread for a delicious vegetarean lunch.
The best way to get maximum flavour into your bechamel is to infuse the warmed milk with parsley, thyme, bay and peppercorns for an hour or so, then strain before stirring into a roux base. In the recipe, I've used a short cut by simply adding the herbs and peppercorns to the sauce while it simmers as the flour cooks out. Not quite as good, but it works fine if you're in a bit of a hurry. The teaspoon of mustard powder gives the sauce just that extra little kick of flavour.
Use all the spring greens, including the outer leaves. Just wash them very well and cut out the tough central stalks. The fleshy leaves add body and texture to the gratin.
Gratin of spring greens, mushrooms and squash
serves four as a side dish, two as a main course
350g spring greens, washed, central stalks removed and sliced into 1 inch strips
1 small butternut squash, peeled and diced
1 tablespoon butter
2 dessertspoons olive oil
3 sprigs of thyme
300g button mushrooms, cleaned and sliced
salt and pepper
150g Parmesan cheese
for the sauce
40g plain flour
1 teapsoon English mustard powder
568ml full cream milk
150ml double cream
5 parsley stalks
2 springs of thyme
5 black peppercorns
Blanch the spring greens in plenty of boiling salted water until just wilted (about one minute) then drain, refresh under cold water and set aside. Saute the squash one tablespoon of butter and a dessert spoon of oil until lightly coloured then add the thyme sprigs and transfer to a hot oven until cooked through which should take about 15 minutes. in the meantime, saute the mushrooms in the remaining butter and oil until they give off all their liquid and take on some colour.
For the sauce, melt the butter in a pan then stir in the flout until it forms a smooth roux mixture. Add the cold milk a little at a time, stirring to avoid any lumps. Bring to the boil, then reduce the heat to a low simmer and add the cream, herbs and peppercorns. Cook gently for 20 minutes to cook out the flour. Add more milk if the sauce is too thick.
In a greased baking dish, combine the all the vegetables and season well with the salt and pepper. Strain over the sauce and mix through well. Grate over the Parmesam cheese and bake in the oven for 20 minutes or until brown and bubbling.