Place potatoes, carrots, and onions in a bowl of a large slow cooker. Place the sausage on top.
In a medium bowl, combine beer, broth, paprika, cumin and pepper. Pour the contents of a slow cooker with this spicy mixture, top with cabbage.
Close the slow cooker and cook on slow power for about 7-9 hours or on high power for 3.5-4.5 hours.
Place the spaghetti in serving bowls and place the stew on them using a slotted spoon. If you wish, you can pour the juice from the stew into the dish. It is good to serve mustard with this dish (optional.)