1. Heat oven to 400°F. Using a sharp knife, cut the pork butt down the middle lengthwise without cutting through. Open butt like a book so it lies flat; season inside and outside with salt and pepper and drizzle with olive oil.
2. Layer garlic, grapefruit slices, shallots, olives, almonds, rosemary and oregano on one side of the butt. Close and tie with kitchen twine every 1 inch.
3. Place stuffed pork butt on rack in roasting pan. Roast until golden brown, about 30 to 40 minutes.
4. Reduce oven temperature to 325°F. Carefully transfer browned butt to a deep, oven-proof pot.
5. Add chicken stock, orange juice and wine. Cover pan and roast 3 hours until very tender, basting occasionally with braising liquid. Internal temperature of pork should be about 200oF. Remove from oven and serve with braising liquid.