Wild Mushroom Lasagne

4tbsp butter

2tbsp olive oil

1 large white onion, sliced

2 garlic cloves, chopped

2 bay leaves

1kg wild mushrooms, sliced

250 ml vegetable stock

1tbsp tomato paste/purée

375g fresh lasagne sheets

300g fontina cheese, grated

50g Parmesan cheese, finely grated

Sea salt and freshly ground black pepper

For the béchamel sauce:

4tbsp/50 g butter

2tbsp all-purpose/plain flour

1/4tsp freshly grated nutmeg

750ml whole milk

To make the béchamel sauce, put the butter in a medium saucepan set over medium heat. When the butter sizzles, stir in the flour and nutmeg and cook for 1 minute, stirring constantly. Remove from the heat and pour the milk into the pan, whisking constantly. Return the pan to low heat and cook for 5 minutes, stirring constantly, until the sauce is smooth and creamy.

Preheat the oven to 180C/Gas 4 and oil a baking dish with half the oil. Put the butter and the remaining oil in a skillet set over high heat and add the onion, garlic, and bay leaves. Cook for five minutes until the onion has softened and turned translucent.

Add the mushrooms, reduce the heat to medium, and cook for 15 minutes, stirring occasionally, until the mushrooms are evenly cooked. Add the stock and tomato paste/purée and increase the heat to high. Simmer rapidly until the liquid has reduced by half. Season well with salt and pepper.

Line the bottom of the oiled baking dish with lasagne sheets. Spread over a third of the sauce. Add one-third each of the mushrooms and grated fontina cheese. Repeat the process and finish with a sheet of lasagne. Spoon over the remaining sauce and sprinkle with Parmesan. Bake in the preheated oven for 45 minutes, until golden brown and bubbling. Leave to rest for 10 minutes before serving.