Combine everything but carrots and parsley in slow cooker and stir to mix. Cook on low for 8-10 hours.
Just before serving, put carrots in microwave-safe dish with about 1/8 cup water. Microwave for 4 minutes. Add carrots to soup with parsley.
Taste and adjust seasonings (I usually end up adding a bit more salt and pepper).
Serve. And serve. And serve.
Notes
Beef: You can either use a whole chuck roast or a packet of stew beef (which is usually chuck roast cut up into chunks). One way or the other, you will need to cut up the meat into smaller, soup-sized piece.
Beef Bouillon: Look for this dried beef broth mix in the soup aisle. You can also use canned or boxed beef broth – use 5 cups and leave the water out of the recipe.
Barley: You are looking for pearled barley, which is usually in the rice aisle of the supermarket.