Melt butter in a large non-stick skillet over medium heat. Add the ground beef and onion. Cook and crumble until the meat is no longer pink. Drain grease.
Add the ketchup, water, brown sugar, Worcestershire sauce, vinegar, chili powder, salt and pepper. Stir well. Let simmer over low heat for 20 minutes.
Meanwhile, bake the Texas Toast in the oven according to package directions. Carefully remove from the oven and leave them on the baking sheet.
Top each Texas Toast with a portion of the sloppy joe mixture. Sprinkle cheese all over the tops. Place back in the oven and bake for another 5 minutes or until the cheese melts. (*watch closely so it doesn’t burn.) Sprinkle the tops with parsley, if desired. Serve and enjoy!