Cut butternut squash into large wedges, place on a baking sheet and add all other ingredients for the squash and place in pre-heated oven 180c for 35-40 minutes Once cooked remove from oven and leave to cool. For the filling, finely chop the leek, onion and pepper. Heat a pan with olive oil and saute until translucent but not coloured, add garlic and rest of herbs and saute for about 1 minute. Set aside to cool.
Remove butternut squash from its skin into a bowl and mash down, add the leek, onion and pepper and mix together, taste for seasoning. Leave to one side until ready to assemble. Wash spinnach, then wilt in a pan and place in a colander to drain, press as much liquid as you can out and leave till cool.
To make the bechamel sauce, put the cold milk into a saucepan, with the onion, carrot, parsley stalks, peppercorns and thyme. Bring to the boil, simmer for 4-5 minutes remove from the heat and leave to infuse for 10 minutes. Whilst the milk is infusing make the roux, melt the 50g butter, add the 50g flour, combine and cook for for 2 minutes on a low heat stirring occasionally. To make the sauce Strain out the vegetables and herbs from the milk, bring the milk back to the boil, and whisk in the roux to thicken to a light coating consistency. Allow to bubble for 4-5 minutes. Season the salt and pepper, taste and correct seasoning if needed, then add the grated cheddar and parmesan and sage.
Bring a a large pan of salted water to boil with a little olive oil, cook the lasagne sheets as per packet instructions. Drain and cover with cold water to stop sticking together. You can now assemble the dish. Preheat the oven to 200oc (fan oven 180oc) Butter a 12" x 9" lasagne dish. Spoon a ladle of bechamel in to the dish and spread to coat the bottom. Place a single layer of lasagne sheets. Spread half the spinnach with a little grating of nutmeg, then half the butternut squash mixture, and half the goat cheese broken up, season with a little black pepper. Spread some bechamel on top, then lasagne sheets, spinnach, butternut squash, sauce and remaining goats cheese and then lasagne. On the top make sure you have enough sauce to cover the sheets and then add the remaining cheeses and pine nuts.* Place in the oven and bake for about 30 mins, until golden.
Allow to rest for 10 minutes before serving.