Boil the potatoes for 20 minutes until tender, then peel and slice them.
Dice the tomato, onion, and smoked pork.
Heat the oil in a frying pan over medium-high heat. Fry the diced smoked pork for 2-3 minutes until browned. Add the onion and fry for 2-3 minutes until softened. Remove both to a plate.
Deglaze the pan with the whipped cream and vegetable stock, scraping up any browned bits. Simmer for 10 minutes. Stir in 100 g of the grated cheese until melted. Season with salt, pepper, and a pinch of nutmeg.
In a greased casserole dish, layer half the potatoes, green beans, diced tomato, and fried pork and onion. Pour half the sauce over and sprinkle with 20 g of cheese.
Add the remaining potatoes, green beans, diced tomato, and pork and onion. Pour the remaining sauce over and sprinkle with 30 g of cheese.
Bake at 200 °C (392 °F) for 20-25 minutes until the top is golden and the casserole is bubbling at the edges.