In a large stock pot or dutch oven, add the onion and ground beef. Cook over medium heat for about 10 minutes, or until meat is browned and onion is cooked through. Use a spoon to remove the grease.

Add the tomato paste, Worcestershire sauce, and mustard, and stir that together for about 2-3 minutes.

Add the beef broth and velveeta. Stir until the cheese has melted, about 5 minutes.

Add the grape tomatoes and lettuce, (it will look like WAY too much, but it will cook down, don't worry) and cook until the lettuce has just barely wilted, about 2 minutes.

Garnish with chopped pickles and cooked bacon.