Molten Grana Padano inside Butternut Squash Wellington with Parma Ham, Cheesy Puff Pastry, Red Wine Sauce, Parsley & Chestnuts

1. Pre-heat your oven to 220°C/Gas 7/Rack position top shelf (both for roasting the squash and baking the Wellingtons).
2. Take the puff pastry out of the fridge to make it easier to unroll.
3. Peel the squash with a vegetable peeler. Cut the bulbous bottoms off the squash about 2cm above the point where they go straight. Now you have 2 circles with a little bump on the top. Cut these in half lengthways. Remove the seeds carefully without breaking through the flesh. Put the squash halves with their empty holes facing up at one end of your baking tray, like little cups. Brush them all over with vegetable oil.
4. Cut the straight part of the squash into 2.5cm dice. Toss this dice with the remaining vegetable oil. Season the squash with salt and freshly ground black pepper. Roast the squash with the 'cups' towards the back of your pre-heated oven, turning the dice occasionally, for 22 minutes or until it is soft and starting to go golden brown. Take the tray out of the oven and let the squash cool completely. Separate the dice into 120g and whatever remains.
5. While the squash roasts, unroll the puff pastry carefully so as not to crack it. Cut the pastry in half widthways. Put the 2 pastry halves on baking paper in the coldest part of your fridge until you need them.
6. Next make the egg wash. Get a small bowl. Add the egg yolk and milk. Mix together with a fork.
7. Get a medium sized bowl. Add the 120g Grana Padano and the mascarpone. Stir together well. Season to taste with salt and freshly ground black pepper. Once the diced squash is cold, fold 120g of it into the Grana Padano mixture. Fill the butternut circles. Wrap these fully in Parma Ham.
8. Get the puff pastry halves out of the fridge. Brush them with egg wash. Leaving a border of 3cm around the edges, sprinkle each half with 2 tbsp Grana Padano.
9. One at a time, as the pastry is easiest to use when it's cold, put the Parma wrapped butternut circles on top of the pastry halves. Lift the edges of the pastry so that they join at the top of the butternut squash and cover it completely. Mould the pastry around the squash, the main thing is that you cover the joint and you may need to stretch the pastry slightly on the thinner side of the rectangles. Turn the now 'Squash Wellingtons' so that their smooth side is up onto baking paper on a baking tray. Brush the pastry thoroughly all over with the egg wash.
10. Bake for 18-20 minutes in the pre-heated oven until the pastry is golden. Add the remainder of the diced butternut squash to the tray after 12 minutes to heat it through.
11. While the Wellingtons bake, make the red wine sauce. Get a medium saucepan, add the porcini, red wine, red wine vinegar and dark soy sauce. Put the pan onto a high heat, bring to the boil and reduce until there are only about 4 tbsp of liquid remaining. Whisk in the whipping cream followed by the 120g butter. Add the butter bit by bit, stirring constantly. Do not let the sauce boil. Season to taste with salt, black pepper and sugar to balance the wine and vinegar. Add the chestnuts to the pan. Keep warm over a very low heat or over a warm water bath.
12. To serve, cut the Wellingtons through the centre widthways with a sharp, thin bladed knife. Spoon the sauce and chestnuts into your plates. Put the Wellington halves cut side up in the middle. Surround with the diced squash and parsley.