Boil the potatoes in generously salted water and drain. Cut the pancetta finely into 3×3 mm dice. Finely chop the garlic. Roughly rub the fennel, cumin and coriander seeds in a mortar.
Put the diced pancetta into a cold heavy bottomed skillet and start gradually warming, until the fat renders. Continue cooking and raising the temperature, until the pancetta pieces fry in their own fat and brown well, about 10 minutes.
Remove pancetta with a slotted spoon and lower the temperature of the skillet to medium. Add lamb mince to remaining fat and start frying, slowly raising temperature until the meat cooks. -Add olive oil if pan seems too dry. Continue frying, stirring constantly. When the juices from the meat have evaporated, add the garlic, dry spices and herbs and continue frying until the meat browns and crisps. Fold in the fried pancetta and season with salt and black pepper.
Warm oven to 225 degrees on the grill setting. Tip potatoes into an ovenproof rectangular dish and squish them with the palm of your hand to lightly break into chunks. Drizzle with olive oil and season with salt. Bake the potatoes in the oven until crispy and browned on the outside, about 15 minutes.
Spoon spicy mince over potatoes and finish dish by grating heaps of Appenzeller Black Label over the dish. Serve immediately.