Step 1: Prepare the Meatballs (if making homemade)
If you are making homemade meatballs, combine the ground beef, egg, breadcrumbs, garlic, salt, pepper, and garlic powder in a large bowl. Mix gently until just combined — do not overwork the mixture, as overworking compresses the proteins and produces dense, tough meatballs. Roll the mixture into balls approximately one inch in diameter. You should get roughly 20 to 24 meatballs from one pound of meat. If you have time, browning the meatballs briefly in a hot pan with a little oil before adding them to the slow cooker adds a layer of caramelized flavor and helps them hold their shape better during long cooking — but this step is optional, and the recipe works well without it. If you are using frozen meatballs, skip this step entirely.
Step 2: Layer the Vegetables in the Slow Cooker
Place the cubed potatoes, sliced carrots, diced onion, celery (if using), and minced garlic into the bottom of the slow cooker. Layering the vegetables on the bottom is important: they take longer to cook than the meatballs and benefit from being in closer contact with the heat source at the bottom of the pot. Distribute them in a relatively even layer.
Step 3: Add the Meatballs and Broth
Place the meatballs on top of the vegetables. In a bowl or measuring cup, whisk together the beef broth, tomato paste, and Worcestershire sauce until the tomato paste has fully dissolved. Pour this mixture over the meatballs and vegetables. Add the oregano, rosemary or thyme, and black pepper. Give everything a gentle stir to distribute the seasoning, being careful not to break the meatballs. Taste the broth and add salt as needed — the amount will depend on the sodium level of your broth.
Step 4: Cook Low and Slow
Cover the slow cooker and cook on LOW for 7 to 8 hours, or on HIGH for 4 to 5 hours. The stew is ready when the potatoes and carrots are completely tender when pierced with a fork and the broth has developed a deep, rich color and aroma. The LOW setting produces a slightly more developed flavor as the ingredients have more time to meld, but the HIGH setting works perfectly well if you need dinner ready sooner.
