Pork and mushroom bake with a potato and butternut squash topping

This is like a shepherds pie but made from pork instead of lamb.  I'm not sure what to call it, maybe Hog herd's pie?  Pigman Pie perhaps?  Let me know what your suggestions are, I may even publish them!  Anyway, this is a lovely winter warmer recipe and is uses the principles of Mediterranean cooking that are supposed to be so good for us, so those of you who think Mediterranean cooking is just about summer food, think again!  It's also a perfect one pot supper dish as it has so many vegetables in it, you really don't need anything else to accompany it.  Perfect for a mid-week meal.

Ingredients
1 tablespoon olive oil
2 medium onions
3 sticks celery
2 onions
4 cloves garlic
500g reduced fat pork mince
100g chorizo (optional) 
250g chestnut mushrooms
A small glass of white wine
300ml chicken stock
Tomato purée
½ a small butternut squash
3-4 small potatoes
2 or 3 gratings of whole nutmeg
Salt & ground black pepper to taste

Method
First, make your Soffritto by peeling and chopping the onion, celery and carrot, heating the oil in a non stick pan and frying the vegetables over a low heat with a pinch of salt to soften.  Make sure you chop the carrot finely or it takes a lot longer to cook.

Heat the oven to 220°C.  While the Soffritto is cooking, peel and chop the garlic cloves, wash and dry the mushrooms and chop them roughly.  If you have time at this stage you can also prepare the squash and potato mash.

Turn the heat up to medium then add the pork mince (along with the chorizo if using) and start to brown the mince.  When everything is taking on a little colour, add wine, turn the heat up to full and reduce the wine by at least 50%.  Add the stock, garlic and mushrooms to the pan, bring to the boil then reduce the heat to medium and cook until the mushrooms have reduced in size and lost their water.  Turn the heat to low, add 4-5 tablespoons of tomato purée, give the whole thing a good stir and leave to reduce for 5 mins so the mix is good and thick.

If you haven't already made the mash, do that now.  Peel and cut the potatoes and squash into 2cm cubes.  To cook the potatoes with the squash, boil a pan of water, add a little salt and add the potatoes.  Boil for 3 minutes, then add the squash and cook until soft.  Drain and mash with a little extra virgin olive oil, salt and black pepper to taste and 2 or 3 gratings of whole nutmeg.

To finish off, tip the meat and vegetable mixture into an appropriate size baking dish and top with the mash.  Don't worry if you don't use all of the meat and vegetable mix, you can freeze the rest for another day.  Bake on the top of the oven until the top is nicely browned and serve as it is.  There are som many vegetables in this dish you don't need and side dishes with it, so an ideal one pot supper!  You can up the carb if you like by having some crusty white bread with it, but it's actually pretty filling as it is.