Instructions:
Preheat oven to 350°F*. Line a baking sheet with parchment paper.
Slice the loaf of bread lengthwise into two halves. Place both halves of the bread onto the lined baking sheet, cut side up.
In a small bowl, combine the butter and garlic salt. Spread the butter mixture over the cut sides of the bread. Set aside while you make the sloppy joe filling.
Sloppy Joe:
In a medium nonstick skillet over medium heat, cook the ground beef and onions until the beef is no longer pink (8-10 minutes). Drain grease. Stir in the garlic powder, mustard, ketchup, salt, pepper, and water, mixing until combined.
Assembly:
Divide the sloppy joe mixture between both sides of the loaves and top with the mozzarella and cheddar cheese. Bake for 12-14 minutes or until golden brown.
Cut into pieces and serve with parsley for garnish.