Line a large rimmed baking sheet with foil and place the bacon in a single layer on it. Put in the cold oven, turn it on to 400°F, and set the tier for 20 minutes. Remove the bacon when it is cooked and crispy (but not overcooked) and drain on paper towels. Dice into small bits when cool enough to handle.
While the bacon is cooking, brown the ground beef in a large skillet. When completely browned, drain any excess grease.
While the beef is browning, melt the butter in a small skillet. Add the onions and garlic and saute until translucent, browned, and fragrant.
With the burner still turned on to medium heat, add the cooked onions/garlic, salt, pepper, chopped tomatoes, and mustard to the ground beef. Stir to combine everything evenly. Add the beef stock and cream and stir. Allow to gently simmer for about 3-5 minutes to allow the mixture to thicken slightly (there will still be liquid in the pan).
Add the diced bacon and the shredded cheese to the skillet. Stir to mix everything together and to allow the cheese to melt into the mixture.
Serve hot over Paleo Waffles (if not low carb) or Low-Carb Cheddar Garlic Biscuits. Spread a little mayo on the waffle or biscuit, add a little chopped romaine, and put sloppy joes on top.