Heat the bacon grease, or olive oil, in a large skillet over medium heat 'til hot.
Sauté the garlic in the bacon grease for 1-2 minutes.
Stir the onion in with the garlic and sauté for another 2-3 minutes.
Add the ground beef into the skillet, stirring the onions and garlic into the meat. Cook on medium heat for 15 to 20 minutes, or until the meat is well cooked. Be sure to drain off any excess oil when the meat has finished cooking.
Mix the ketchup, Worcestershire sauce, and brown sugar into the meat, stirring until combined.
Let the sloppy joe mixture simmer over low to medium heat for at least 5 minutes.
Meanwhile, prep your bread and cheese. Butter the outside of 2 slices of bread, and repeat with a set of slices for each person you’re feeding.
Once the sloppy joe meat is finished cooking, add the desired amount of meat to each sandwich.
Then add 2 or 3 slices of each person’s favorite cheese.
Slap the cover on your sandwich, and fry it in a skillet or on a griddle over low heat 'til each side is golden and the cheese has melted, probably about 5-10 minutes.
Once your sandwiches are grilled, they're ready to serve with your favorite side!