Finely chop the shallot and garlic. Slice the chestnut mushrooms. Finely grate the parmesan cheese and roughly chop the parsley. This is your veg prep done!
Heat the butter and oil in a large non stick frying pan over medium heat. Add the shallot and garlic, let these soften for a minute before adding the mushrooms and thyme. Sauté for 5-6 minutes until the liquid has evaporated and they have browned a little, don’t stir during this stage too much. Season to taste then set aside and leave to cool. Blitz this in a food processor, tip into a bowl and stir through the parmesan, breadcrumbs and herbs.
Preheat the oven to 180c. Line a large baking tray with parchment paper.
Butterfly the chicken breast and then using a rolling pin, bash to give an even thickness. It should be around the size of an a4 sheet. Spread this across the turkey and then from one of the shorter ends, roll tightly to give you a spiral pattern.
Roll the pastry out the same shape as the rolled turkey but leaving about 5cm all around, or enough to roll it around the turkey. Using a pastry brush, brush the inside of the pastry with the egg. Arrange the turkey on this and then roll so it’s seam side down.
Brush the outside of the pastry with egg. Use a small sharp knife to score the pastry but don’t cut fully through. Create a diamond pattern on the surface. You can roll any excess pastry and cut into leaves or other patterns if you like. Sprinkle with sea salt and the rosemary leaves.
Place in the middle shelf of the oven for an hour until golden then leave to rest for about 10 minutes before slicing and serving with cranberry sauce and roast vegetables.