Creating Tuna Melt Casserole can be done effortlessly if you follow these simple steps:

1. Preheat your oven to 350°F (175°C).
2. Prepare an 8×8 inch baking dish by greasing it with non-stick spray or butter.
3. In a large bowl, combine the flaked tuna, mayonnaise, milk, garlic powder, black pepper, and salt. Mix until well combined.
4. Add the bread cubes, chopped onion, chopped celery, and peas (or mixed vegetables) to the tuna mixture. Stir gently to coat the bread evenly.
5. Fold in the shredded cheddar cheese, mixing just until combined. Reserve a small amount of cheese for topping.
6. Transfer the mixture to the prepared baking dish, spreading it evenly.
7. Top with crushed potato chips if using, and sprinkle with the reserved cheese.
8. Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and golden brown on top.
9. Remove from the oven and allow to cool for a few minutes before serving.

These steps will guide you through creating a beautiful Tuna Melt Casserole that everyone will love!