Step 1: Prep and Preheat

• Preheat your oven to 375°F (190°C).
• Grease a 9×13-inch baking dish or line it with parchment paper for easy cleanup.

Step 2: Cook Potatoes

• Place diced potatoes in a large pot and cover with salted water.
• Bring to a boil, then reduce heat and simmer for about 10 minutes, or until just tender. Drain and set aside.

Step 3: Make the Sauce

• In a large bowl, combine the cream of mushroom soup, sour cream, milk, garlic powder, salt, and pepper. Mix until smooth.

Step 4: Combine Ingredients

• Add the cooked potatoes, ham, shredded cheddar cheese, and chopped onion to the sauce. Stir until everything is evenly coated.

Step 5: Assemble

• Pour the potato and ham mixture into the prepared baking dish. Spread it out evenly.
• In a small bowl, mix the breadcrumbs or crushed crackers with melted butter. Sprinkle this mixture over the top of the casserole.

Step 6: Bake

• Bake in the preheated oven for 30-35 minutes, or until the casserole is bubbly and the topping is golden brown.

Step 7: Rest and Serve

• Let the casserole rest for 5 minutes before serving. Garnish with fresh parsley or chives if desired.