In a large bowl, combine beef, salt, and ras el hanout. Let sit at room temperature at least 1 hour or up to 24 hours in the refrigerator.
In a cast iron pan, heat olive oil to medium heat. Add add garlic and ginger and stir continuously for no more than a minute, until they become fragrant. Stir in tomato paste and stir continuously for another 3 minutes, until the paste changes color. Working in batches, add beef and cook only until browned on all sides. Set aside as the beef is browned, and continue until all the beef is cooked.
Soak raisins in enough water to cover completely. Drain water after 30 minutes.
Combine beef stock, kohlrabi, carrots, date paste, and beef in a ceramic casserole pan. Cover with foil and cook in oven for 1 hour.
If not using a tagine, add whole dates to the casserole pan and cook for another 30 minutes, or until beef is tender.
If using a tagine, place diffuser and tagine on the stove and raise heat to medium-low. Add whole dates to the casserole pan, and remove from oven. Working in batches, transfer some of the contents to the tagine. Heat with the lid on for another 30 minutes or until the beef is tender. Repeat as needed until done.
Stir in soaked raisins.
Garnish with cilantro and serve with flatbread or couscous.