Heat half of the olive oil in a deep ovenproof frying pan on medium-high heat. Brown the pork pieces in batches until seared all over, then transfer them to a plate. If needed, add another tablespoon of oil to the pan while cooking the batches. Once all the pork is seared, transfer it to a plate and set aside.

In the same pan, add another tablespoon of olive oil and a small amount of butter. Fry half of the leeks with a pinch of salt for 10 minutes or until tender. Add the garlic and fry for another minute, then stir in the flour.

Gradually pour in the cider, a little at a time, while stirring to scrape up any bits stuck to the bottom of the pan. Add the chicken stock, bay leaves, and the seared pork. Simmer the mixture, partially covered with a lid, for 1-1 30 hours until the meat is just tender. Note that it will continue to cook and become tender in the oven. This step can be done a day ahead and refrigerated.

Preheat the oven to 200C/180C fan/gas 6. Simmer the mixture uncovered for a few minutes to reduce the sauce if needed. The sauce shouldn't be too liquid, as the potatoes may sink into it. Stir in the parsley, chopped sage, remaining leeks, and the cream. Season well with salt and pepper.

Peel both types of potatoes and cut them into 2mm thick slices. Arrange alternating layers of potato and sweet potato slices in circles or randomly. Dot the cubed butter over the top. Bake the hotpot for 1-1 30 hours until the potatoes are tender. In the last 10 minutes of baking, nestle whole sage leaves, brushed with a little oil, into the dish. Allow the hotpot to rest for 10 minutes before serving.