Place the beef shoulder in an oven-safe dish with a tight-fitting lid. Add the vegetables and wine, and then pour in enough beef stock to cover the meat halfway. Reserve the remaining stock. Braise in the oven, covered, until a fork easily pierces the meat, about 2 hours 30 minutes. Once the meat is cooked, remove from the liquid. Strain the liquid and discard the vegetables, then return the meat to the liquid and refrigerate overnight.
Preheat the oven to 350 degrees F.
Place the potatoes in a pot of cold, salted water and cook until a knife easily pierces all the way through. Drain and let cool to room temperature. Meanwhile, combine the chickpeas and remaining beef stock and simmer until tender (add water as needed to ensure the chickpeas stay covered).
Heat a small amount of oil in a saute pan; add the carrots and cook, stirring occasionally, until just tender. Remove and season with salt, black pepper and the sugar (to take away any bitterness). Heat a small amount of oil in a saute pan again and cook the cabbage slices in batches until each piece is nicely browned on one side. Toss with some salt and pepper and return to the pan, cooking until just tender.
For serving: Remove the beef from the braising liquid and set aside. Place the chickpeas, potatoes and braising liquid in a pot and heat to warm through for serving. Add salt and mojo picon to taste and transfer to a large, ovenproof serving vessel. Select a few large pieces of the beef and sear in a saute pan until a brown crust forms on the outside. Add the beef, chorizo and sausage to the chickpea and potato mixture and bake until the sausage is heated through.