01 -
Heat a large skillet over medium-high heat. Add diced onion and ground beef, seasoning with beef bouillon powder, salt, and pepper. Cook for 8-10 minutes, breaking up the meat, until no pink remains and onions are softened.
02 -
Add minced garlic and cook for 30-45 seconds until fragrant. Drain off excess grease from the skillet to prevent the mixture from being too oily.
03 -
Add tomato sauce, ketchup, mustard, and brown sugar to the beef mixture. Stir everything together until well combined and bring to a gentle simmer over low-medium heat. Cook for 5-7 minutes until the sauce thickens slightly.
04 -
Heat a separate skillet or griddle over medium heat. Spread a thin layer of mayonnaise on one side of each piece of Texas toast - this will be the outside of your sandwiches.
05 -
Place 6 slices of bread mayo-side down in the skillet. Top each with a slice of cheese, then add a generous scoop of the sloppy joe mixture (about ⅓ cup per sandwich).
06 -
Add another slice of cheese on top of the sloppy joe mixture, then top with the remaining bread slices, mayo-side up. Cook for 3-4 minutes per side until golden brown and the cheese is melted.
07 -
Remove from heat and let cool for 1-2 minutes before cutting. Cut diagonally and serve immediately while the cheese is still gooey and the filling is hot.