1.Prick potatoes all over with a fork; microwave on HIGH (100%) for 5 minutes or until tender. When cool enough to handle, cut each potato into six wedges.
2.Meanwhile, shred chicken and skin, reserving bones.
3.To make gravy, melt butter in a small saucepan over medium heat. Once foaming, add flour; cook, stirring, for 1 minute or until dry and golden. Add shallot and chicken bones; stir a further 2 minutes or until shallot softens. Increase heat to medium-high. Gradually stir in stock; cook, stirring, for 4 minutes or until thickened and reduced by a quarter. Remove and discard bones; season to taste. Cover gravy to keep warm.
4.Meanwhile, preheat grill to high. Heat a small ovenproof frying pan over medium-high heat. Cook potato, turning occasionally, for 6 minutes or until golden. Drain off excess oil. Top potato with chicken; sprinkle with mozzarella, heat under grill for 4 minutes or until mozzarella melts and chicken is warmed through. Pour gravy over top; sprinkle with parsley to serve.
Any all-rounder potato variety, such as sebago or spunta, can be used instead of desiree potatoes. You could use 2 rashers of bacon in place of the chicken.