You don't need duck to make this recipe, as stuffed cabbage is good with any meat. Other than that, this is a pretty easy recipe to make, with standard ingredients.
Bring a large pot of salty water to a boil. Boil the cabbages -- probably one at a time -- for 5 minutes. Run them under cool water until you can handle them, then gently remove as many large leaves as you can; these are what you will use as wrappers. Set the leaves on a towel while you make the sauce and filling.
Cook the bacon dice until they are crispy, then set aside. Add the chopped onion and carrot to the pan and cook on medium heat until the onion turns clear, about 6 minutes. Add the garlic and cook another 90 seconds. Add the white wine, tomatoes, chopped apple and 2 tablespoons of parsley, along with the thyme and salt to taste. Simmer gently while you make the filling and stuff the cabbages.
While the sauce is simmering, soak the dried bread in the milk for 15 minutes, then squeeze out the bread to remove excess milk. Mix everything else together, along with 2 more tablespoons of parsley, until it holds together like meatloaf.
Lay out a cabbage leaf with the stalk facing you and place some filling inside; amounts will differ, as the leaves are different sizes. Fold the stalk end over the filling and then fold in the sides, then give the leaf one more roll to secure; this is like folding a burrito or a package. Repeat until you have used all the filling.
Pour the sauce into a blender and puree. Add salt and black pepper to taste. Arrange the stuffed cabbages seam side down into a wide, shallow pan with a lid, then pour over the sauce. Jiggle the pan to coat everything. Sprinkle the reserved bacon over it all, cover and simmer for 45 minutes to 1 hour. Serve with the remaining parsley sprinkled over the top.
Notes
Note that you will not be using all the cabbage you need for this recipe. Plan on using the center cores of the cabbage for slaw or some other dish, like Mexican salpicon.