Preheat oven to 350°F (175°C). Grease a 9×13-inch baking dish.
In a skillet over medium heat, cook ground beef with diced onion until browned. Drain excess fat.
Stir in ketchup, mustard, mayo, garlic powder, onion powder, salt, and pepper. Remove from heat and fold in cooked bacon.
Add half the cubed bread to the bottom of the casserole dish.
Layer with half the cheddar and mozzarella cheese.
Spoon the beef mixture evenly over the cheese.
Add the remaining bread cubes and top with the remaining cheese.
In a bowl, whisk eggs, milk, and melted butter. Pour evenly over the casserole.
Bake for 30–35 minutes or until golden, melted, and bubbling.
Let rest 10 minutes before serving. Add optional pickle slices on top.
Enjoy 🤤😋
