Mix the potatoes with all the other ingredients up to and including the salt, spread onto a baking tray lined with baking paper.
Mix the mustard with all the other ingredients up to and including the salt. Coat the chicken legs with the mixture, place on top of the potato mixture.
Approx. 45 mins. in the lower half of an oven preheated to 220°C.
Heat the butter in a pan. Sauté the shallot. Pour in the wine and cream, add the rosemary, bring to the boil, simmer over a medium heat for approx. 5 mins., stir in the mustard, season. Serve with the chicken.