Place 2 tbsp goose fat or olive oil in a roasting pan and place in an oven at 200c for a few minutes till nice and hot. Remove from the oven and add 300g new potatoes and 300g Jerusalem artichokes scrubbed and sliced in half lengthwise (they should sizzle as they hit the pan). Sprinkle on some smoked paprika, dried thyme, sea salt and pepper and return to the oven to bake for around 25-30 minutes till nice and golden, flipping over the vegetables once during cooking.