Set the slow cooker to low heat. Allow it to warm while you prepare the broth ingredients and brown the beef.

Combine the beef stock, tomato, pickles, Dijon mustard, Worcestershire sauce, parsley, salt, and pepper in the slow cooker. The broth should look well seasoned and lightly speckled with herbs and pickles.

Brown the ground beef, onion, and garlic in a large skillet over medium-high heat, then drain away the excess grease and transfer the mixture to the slow cooker. Cook the covered soup for 6 hours, until the beef flavor has fully worked into the broth and the onion is tender.

Stir in the cheddar cheese and heavy cream, then continue cooking for 1 additional hour. Keep the heat gentle so the cheese melts into a cohesive, creamy broth rather than forming oily streaks.

Scatter in the crumbled bacon just before serving. The bacon should remain crisp enough to float on top instead of disappearing into the soup.

Warm a large Dutch oven or stockpot over medium heat, then cook the ground beef with the onion and garlic. Break up the beef as it cooks until no pink remains and the garlic smells fragrant without browning too darkly.

Pour in the beef stock and add the tomato, pickles, Dijon mustard, Worcestershire sauce, parsley, salt, and pepper. Bring the mixture to a boil, then lower the heat to medium-low and simmer for 30 minutes so the flavors meld.

Lower the heat and stir in the cheddar cheese and heavy cream, cover the pot, and cook for 30 minutes while stirring occasionally. The soup should stay at a quiet simmer and become creamy and glossy as the cheddar fully melts.

Stir in the crisp crumbled bacon immediately before serving. Leave a little bacon on top of each bowl for the best smoky crunch.