Peel and cut the potatoes into 1-inch cubes, placing them in a bowl of cold water to prevent browning—this keeps them looking fresh. Dice the onion into 1/2-inch pieces, mince the garlic cloves finely, and shred the cheddar cheese from a block (pre-shredded cheese often contains anti-caking agents that prevent smooth melting). Have all your seasonings measured and ready to go, as you'll be working quickly once the beef starts cooking.

Heat a large skillet over medium-high heat and add the ground beef, breaking it into small pieces as it cooks. Cook for 5-7 minutes, stirring occasionally, until the beef is fully browned and no pink remains. I prefer an 80/20 lean-to-fat ratio because it renders enough fat for flavor while keeping the soup from being greasy. Drain the cooked beef in a colander to remove excess fat, which would otherwise make the soup overly rich.

Transfer the browned beef from Step 2 to your slow cooker. Drain the potatoes from their water and add them along with the diced onion and minced garlic. Pour in the beef broth, diced tomatoes, and cheddar cheese soup, stirring everything together to combine. Add the measured herbs, salt, and pepper, then stir in the milk until well blended. The aromatics from the fresh garlic and onion will infuse the broth as it cooks, creating a flavorful foundation.

Cover the slow cooker and cook on low for 6-8 hours, or on high for 3-4 hours if you're short on time. The potatoes will soften and break down slightly, thickening the broth naturally while the flavors meld together. Low heat is preferable for developing deeper flavor and a better texture, though high heat works when needed. Resist the urge to peek frequently, as opening the lid extends cooking time.

During the last 30 minutes of cooking, remove the slow cooker lid and stir in the shredded cheddar cheese from Step 1 and the heavy cream. Stir well to ensure the cheese melts smoothly and the cream incorporates evenly—this creates the signature creamy, rich texture. The heavy cream adds luxurious mouthfeel that milk alone can't achieve, and adding it near the end prevents any curdling that might occur from prolonged cooking. Taste and adjust seasonings if needed.

Ladle the soup into bowls and garnish generously with fresh parsley. The bright green color and fresh herb flavor provide a nice contrast to the rich, creamy soup.