Place sliced onions and garlic on the bottom of a 9x13 pan. Sprinkle with salt and pepper. Place roast into pan and sprinkle onion soup mix on top.
Pour duck sauce and chicken stock over roast. Pour wine over roast.
Cover with parchment paper and seal the pan with heavy silver foil.
Bake for 3 hours basting every ½ hour. When roast is done, wrap it with silver foil and refrigerate so you can slice it nicely. Blend sauce to be used later when reheating meat slices. Freezes very well for later use.