Marinate shanks: Mix garlic, ginger, oil, and soy sauce. Trim membrane from shanks (it shrinks during cooking and buckles the meat). Tie shanks around their girth with twine, then arrange in a large roasting pan in a single layer. Add chiles; pour in marinade. Chill at least 6 hours and up to overnight, turning once.
Braise shanks: Two hours before cooking, take shanks out of refrigerator. Put on a baking sheet (discard marinade) and dry with paper towels. Sprinkle with salt, then ras el hanout. Rinse and dry roasting pan.
Preheat oven to 325°. Heat roasting pan or 2 large dutch ovens over medium-high heat on stovetop and pour in oil. Add shanks and brown on both sides. Pour in wine and sherry, scraping up brown bits.
Add remaining ingredients to roasting pan (if using short ribs, add vegetables after 1 hour). Bring to a simmer, then cover tightly with foil. Put in oven and braise until a knife tip slides in easily, 2 to 2 1/2 hours (about 3 hours for short ribs).
Lift shanks and about half of vegetables to a platter; keep warm, covered with foil. Set pan with remaining vegetables on stovetop and boil over medium heat, stirring occasionally, until juices reduce by about half and thickly coat the back of a spoon, 20 minutes. Strain (spoon off fat if using short ribs) and serve with shanks.
*Free-raised refers to calves raised on open pasture; available at some butcher shops and at Whole Foods Market, often labeled "Humanely Raised" or "Certified Humane." Find harissa, a North African chile paste, at well-stocked grocery stores. Its heat level varies by brand, so taste a little before using.