Preheat the oven to 180 degrees and lightly grease a Pyrex Magic springform.
Place the winter squash and parsnips in to a steamer for 10 minutes until they soften.
Fry the onion and leeks for 3 minutes, then add the garlic and fry for a minute, and then the mushrooms and herbs and cook through for a further minute.
Remove from the heat and allow to cool.
Place the nuts on a Pyrex magic baking tray and roast in the oven for 6-8 minutes.
Once the nuts have cooled, finely chop and add them to a bowl along with cheese, parsnips, squash, cranberries and leeks.
Whisk together three eggs, season and add to the mixture.
Knead the pre-made short crust pastry and divide 1/3 for the lid.
Roll the remainder out on a lightly floured surface until it is 5mm thick.
Carefully lift it into the Pyrex Magic springform, easing it into the corners; trim off the excess pastry, leaving 1cm hanging over the edge of the tin.
Spoon the filling into the tin and press it down and brush the exposed pastry rim with the beaten egg.
Roll out the remaining pastry to 5mm thick then cut out a circle 1cm wider than the spring form.
Place the pastry over the top of the pie and press the edges together to seal.
Cut a slit in the middle to let any steam escape.
Brush the top of the pie with the remaining egg.
Bake for 1 to 1½ hours until hot all the way through.
Remove from the oven and leave the pie to cool in the tin for 10 minutes then carefully remove it.
Tips
Cover the top of the pie with tin foil after 20 minutes or so to prevent it from burning.
6 - 8 slices
around 2 hours