Place the beef stew meat, onion, and garlic in the slow cooker. Sprinkle the cumin, smoked paprika, cinnamon, salt, and pepper over the meat and stir to coat.
Pour the Guinness and beef broth into the slow cooker. Add the carrots, parsnips, and potatoes and stir once to combine.
Cover and cook on low for 8 hours until the beef is fork-tender and the vegetables are soft.
Stir in the chopped kale during the last 15 minutes of cooking so it wilts but keeps its bright color.
Taste and adjust salt or pepper if needed before serving.