In a medium saucepan combine the beans and 2 quarts of water and bring to a boil over high heat. Reduce heat to a simmer and cook for 10 minutes. Cover, remove from the heat and let stand for 45 minutes to 1 hour. Drain and discard the soaking liquid. Return the beans to the pan and add enough water to cover by 2 inches. Return to a simmer and cook for 30 minutes, or until beans are al dente. Strain and reserve bean cooking liquid.

Preheat the oven to 350 degrees F and position the oven rack in the lower 1/3 of the oven.

In a resealable plastic bag, combine the confectioners' sugar, salt and black pepper, to taste. Add the lamb cubes and shake to coat. In a large, ovenproof Dutch oven over high heat, heat the vegetable oil until hot. Add the butter and, working in batches, brown the lamb cubes and onions until well browned on all sides, about 10 to 15 minutes. Be careful not to burn the sugar. (If the sugar begins to burn on the bottom of the pan before you're finished, add a bit of water and scrape the pan bottom to remove the browned bits, adding more oil and butter as necessary for subsequent batches.)

When the lamb and onions are all browned, add the red wine, reserved beans, garlic, bay leaves, parsley, thyme, paprika, cayenne pepper, baking potatoes and tomato puree and enough of the reserved bean cooking liquid just to cover. Cover and bake for 1 1/2 hours, or until the lamb and beans are tender. Season with salt and pepper, to taste, before serving.