Slit the skin of the duck breasts and rub in a little salt and crushed pepper.
Put aside on a plate in the refrigerator.
Wash the potatoes and brush the skin without peeling.
Place in a saucepan with a large quantity of cold water and sea salt.
Boil for around 30 /35 min.
Remove the skins from the potatoes and mash with a fork, gradually incorporating 5 tablespoonfuls of Lesieur olive oil and the mustard.
Put aside the mashed potatoes in a bowl placed over a pan of hot water.
Heat 1 tablespoonful of Lesieur olive oil in a frying pan and add the duck breasts, skin side down. Cook for 10 min.
Pour off some of the fat, turn the breasts and continue cooking for 5 min.
Put aside on a plate.
Discard the fat, then pour the honey into the frying pan with the vinegar and 2 spoonfuls of water.
Reduce for 3 min.
Arrange the potatoes on a plate with the halved breasts and coat with the honey sauce.