Prepare the turkey as per Slow Roast Turkey Leg and cook in the oven for 2 hours at 160C / 140C fan / gas mark 3 / 325F.
Peel the potatoes and cut into 30g pieces (ish!) Place in a saucepan and cover with just boiled water from the kettle. Cook for 10 minutes on a medium-high heat - start timing from the moment you turn on the heat.
Start preparing the stuffing balls as per Easy Peasy Stuffing Balls.
Drain the potatoes and put them back in the saucepan. Put the lid on and shake the pan to rough up the edges. Remove the lid. Finish preparing the stuffing balls.
Place the stuffing balls in the oven and cook for 20-25 minutes or until they are golden brown and cooked through.
Turn the heat up to 220C / 200C fan / gas mark 7 / 425F, then take the turkey roasting tin out of the oven and remove the foil. Check there is enough liquid in the base. (Add a splash of boiling water if not.) Return the roasting tin to the oven and cook the turkey for a further 30 minutes to crisp up the skin.
Drizzle a baking tray with enough oil to nearly coat the bottom of the tray and sprinkle with a little salt and pepper. The baking tray should be large enough to fit all the potatoes in a single layer.
Peel and halve the sprouts. Peel and cut the parsnips and carrots into batons. Place the prepared parsnips in a shallow roasting tray and drizzle with olive oil. Scatter over a little salt and pepper to taste. Toss everything together, so the parsnips are well coated, then arrange in one layer.
Remove the baking tray from the oven and then tip the cooked potatoes into the baking tray, taking care not to splash yourself with hot fat, and turn the potatoes in the oil to coat them. Put the potato tray straight back into the oven.