Heat the oven to 200 degrees and line a large baking tray with baking parchment,
Place the squash, leeks and sprouts into a mixing bowl and sprinkle over the rosemary, sea salt and lots of olive oil then mix thoroughly and transfer the veg to the baking tray,
Roast for 30-40 minutes,
Allow the veg to cool slightly before transferring the veg back to a mixing bowl and adding in the baby spinach, cheeses and cranberries. Mix well.
Turn the oven down to 180 degrees then line another large baking tray with baking parchment,
Place a sheet of filo onto the baking tray and coat with melted butter then repeat this process until you have used half the packet (around 6 sheets),
Place the vegetable mixture down the central part of the filo pastry in a line using 2/3 of your mixture or more if the pastry will allow,
Fold in one side of the pastry to the centre followed by the other side and turn the strudel over so the seam is on the bottom of the strudel,
Cover with melted butter using a pastry brush and bake for 30 minutes.
This strudel can be enjoyed for one or two days after you have made it. Gently re-heat in the oven covering any of the cut ends with foil to prevent the strudel from drying out.