Season the chicken with salt and pepper, let sit for 10 minutes.
Heat a large frying pan with 2 tablespoon oil over medium heat. Stir-fry the garlic and shallots until aromatic, 2-3 minutes. Add the chicken skin-side down and cook until the skin turns brown, 3-4 minutes. Flip over and continue to cook until done, about 3-4 minutes.
Add 125ml to the pan and bring to the boil, reduce the heat, cover and simmer for 3-5 minutes or until the juices of the chicken run clear. Set aside and allow to cool.
Pre-heat the oven to 150 C / Gas 2.
Spread just enough mustard on the chicken skin to coat evenly. Sprinkle with rosemary, then coat with breadcrumbs.
Place the chicken onto a baking tray. Bake until the chicken is heated through and the breadcrumbs are brown and crunchy. Serve.