Heat the oven to 200C/180C fan/ gas 6. Tip the squash onto a large baking tray, drizzle with 1 tbsp oil, season well and toss to coat. Cut off the top of the garlic bulb to expose the cloves inside, sit on a square of foil and drizzle with a little oil, then enclose in the foil. Put on the tray with the squash and bake for 45 mins, stirring the squash every 15 mins until it is evenly coloured.

Meanwhile, tip the dried mushrooms into a heatproof bowl and pour over 500ml boiling water. Leave to soak for 10 mins. Heat 2 tbsp olive oil in a large frying pan over a medium heat and fry the wild mushrooms for 10 mins, or until any liquid has evaporated and the mushrooms have browned. Chop 5 sage leaves and add to the pan. Season well and pour in the wine, if using. Bubble until the alcohol has evaporated, then pour in most of the soaking liquid from the dried mushrooms (avoid the last dregs, as this may contain grit). Cook for another 10 mins until reduced by half. Chop the rehydrated mushrooms and stir into the sauce.

Stir 250g mascarpone into the sauce and cook, stirring until smooth. Add the roasted squash. Squeeze the roasted garlic from the bulb onto a chopping board and squash into a paste using the blade of a knife, then add to the sauce. The sauce should be the consistency of double cream at this stage – if it’s too thick, add a splash of water.

Spoon roughly half of the sauce into an ovenproof dish (roughly 26 x 20cm). Cover with a layer of lasagne sheets, then repeat using the remaining lasagne sheets and sauce, finishing with a layer of pasta.

Combine the remaining 150g mascarpone with half the cheese and the milk. Spread the mixture over the top layer of lasagne sheets, then scatter with the remaining cheese and season with black pepper. Rub the remaining sage leaves with the rest of the oil and arrange on top of the lasagne. Will keep covered and chilled for up to a day or frozen for a month. Defrost fully before baking.

Heat the oven to 180C/160C fan/ gas 4 and bake the lasagne for 35-40 mins until golden and bubbling. Serve immediately.