Preheat the oven to 350 degrees F.
Clean the beef shoulder and then split it in half. Rub meat with garlic. Heat oil in a large pan over medium-high heat, and then add beef and sear until golden brown on all sides. Add cranberry juice and deglaze pan, scraping the bottom with a wooden spoon to remove any browned bits. Transfer beef and pan juices to a roasting pan with the Cranberry Sauce and Veal Stock. Roast for approximately 5 hours, or until meat is completely tender and pulling apart. Serve with Garlic Mashed Potatoes.
Place all ingredients in a medium saucepan and slowly bring to a simmer over medium heat. Reduce heat to medium-low or low and let sauce reduce until thickened and the sauce "comes together," about 1 hour.
Preheat oven to 400 degrees F.
Roast the bones in the oven for 1 hour. Put the roasted bones in a large pot and add water to cover. Add all other ingredients and simmer for 24 hours. Drain stock and discard bones.
Place the potatoes in a large pot and cover with cold water. Over medium heat, bring to a simmer and cook until the potatoes are tender. Drain potatoes and add to a mixing bowl. Add all remaining ingredients and mash with an electric mixer or hand mixer to desired smoothness.