Season the duck breasts and place skin side down in a medium heated, thick saute pan. Slowly render the duck fat away (12 to 15 minutes). When the skin browns, let breast rest, meat side down. Just prior to plating wipe out pan and bring to high temperature and quickly sear the duck, meat side first, then the skin side, 3 minutes total. Let rest again before slicing.
For the sauce, caramelize the shallots in a saucepan with a little canola oil. Season. Deglaze with cognac and reduce by 75 percent. Add the chicken stock and reduce by 50 percent. Pour into a blender and monter au foie gras. In other words, as liquid is blending, add foie gras pieces to blender. Check for seasoning and keep warm for plating.
RED CABBAGE SLAW:
Mix mustard with lemon juice. Whisk in oil and check for seasoning. Toss with cabbage and scallions. This slaw may be done 20 minutes before plating.
WITH CHINESE AND BALSAMIC VINEGAR EMULSION
In a non-reactive sauce pan, reduce the two vinegars by 80 percent until a syrup consistency is achieved. Pour the syrup into a blender while hot. While blending at high speed, drizzle in canola oil. Check for seasoning. Caramelize red onions in a saute pan coated with a little canola oil. Set aside. In a non-stick pan, coat well with canola oil and saute potatoes until golden brown. Season with salt and pepper. Toss hot potatoes with the onions and vinegar emulsion. Check for seasoning.