Preheat the oven to 350F. Prick the potatoes with a fork and bake them for 1 hour. Place the spare ribs in a shallow ovenproof dish and brush them with half the barbecue sauce. Leave to stand for 1 hour. Increase the oven temperature to 425F. Remove the potatoes from the oven and wrap them in foil. Place the spare ribs on a rack and bake them for 1 hour, brushing them once or twice with the barbecue sauce. To serve, cut open the baked potatoes and place a tablespoon of butter on each one. In a small bowl whisk together the fromage blanc, crÅme fraöche, 2 tablespoons water and the herbs. Serve the ribs with the mustard sauce and creamy herb sauce.
