Peel and slice the onion and garlic, slowly cook in a pan without colour. When soft add the wine and reduce until completely gone.
Peel the potatoes and butternut squash, slice thinly by hand or on the mandolin. Season with salt and pepper and mix well.
Mix the cream and milk. Put the onion mix in the base of an oven dish and layer the potatoes and squash on top, adding your sage and sliced cheese as you go, cover with the cream mix and place a little more of each cheese on top. Cover with foil.
Place in the oven at 160C for 2 hours. Remove the cover and place back in the oven at 180C for around 30 minutes or until nicely coloured on top.
