In a sauté pan, pour the vinegar and add the sugar, bring to the boil, reduce until the liquid becomes syrupy and coats the spoon.
In a hot non-stick pan, fry the duck breasts previously incised on the skin for 5 minutes skin side down. Flip them over and continue cooking for 3 minutes on the other side. Season. Keep them warm in a sheet of aluminum foil.
Discard the cooking fat from the duck breasts. Add a knob of butter (15 g), let melt and fry the cherries for 2 to 3 minutes. Pour them into the vinegar reduction and add the veal juice, cook for 5 minutes.
Cut the duck breasts into slices. Add the drained cherries. Just before serving, stir the rest of the butter into the sauce. Whisk briskly and coat the meats and fruits with this sauce.
Serve with small Noirmoutier potatoes cooked in their skins.
Note:out of season use frozen or canned fruit.