Cheesy Ham and Potato Casserole Step-by-step instructions

Before you start

Before starting, gather all the ingredients and measure them out accurately. Wash, peel, and dice the potatoes into uniform half-inch cubes to guarantee even cooking. Dice the cooked ham into similar bite-sized pieces.

Shred the cheddar cheese from a block rather than buying pre-shredded cheese, as freshly grated cheese melts much smoother and creates that perfect stretchy pull. Preheat the oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish with butter or non-stick cooking spray to prevent sticking.

Instructions

Cream Sauce Preparation and Mixing

1. 1Prepare the Cream Sauce
   In a large mixing bowl, combine the sour cream, heavy cream, garlic powder, onion powder, salt, and black pepper. Whisk the ingredients together vigorously until the mixture is completely smooth, uniform, and free of any lumps. This creates the flavorful, velvety base that will coat the potatoes and ham.
   Look for The sauce is smooth and fully blended.
   Tip Ensure the sour cream is at room temperature to prevent clumping.
2. 2Combine the Ingredients
   Add the diced Russet potatoes, diced cooked ham, and one cup of the shredded cheddar cheese to the bowl with the cream sauce. Use a large spatula to gently fold the ingredients together until the potatoes and ham are thoroughly and evenly coated with the cream sauce.
   Look for Every piece is coated in the cream mixture.
   Tip Cut the potatoes into uniform half-inch cubes for even cooking.

At the end of this first phase, the sour cream, heavy cream, and spices should be whisked into a completely smooth, uniform sauce with no visible lumps.

Once the diced potatoes, savory ham, and initial portion of cheddar cheese are folded in, every piece should be thoroughly and evenly coated in the velvety mixture. The mixture should look thick and creamy, holding its shape in the bowl without being overly runny, ready to be transferred to the baking dish.

Baking the Casserole Base

3. 3Assemble in the Baking Dish
   Grease a 9x13-inch baking dish with butter or cooking spray. Transfer the potato, ham, and cheese mixture into the prepared dish, using a spatula to spread it out into an even, flat layer that fills the corners of the dish.
   Look for The mixture is spread evenly in the dish.
   Tip Press down gently to compact the mixture slightly for better baking.
4. 4Bake the Casserole
   Place the baking dish into a preheated oven at 375°F (190°C). Bake uncovered for 40 minutes, or until the potatoes are completely tender when pierced with a fork and the sauce is bubbling actively around the edges.
   Look for The potatoes are tender and the edges are bubbling.
   Tip If the top starts to brown too quickly, cover loosely with foil.

After the main baking period, the casserole should be bubbling vigorously around the edges of the baking dish. The potatoes must be completely tender when pierced with a paring knife or fork, offering no resistance. The cream sauce will have thickened slightly and absorbed the savory flavors of the ham. The kitchen should be filled with a rich, comforting aroma of roasted potatoes, garlic, and savory baked ham.

Cheese Melting and Broiling

5. 5Add the Cheese Topping
   Carefully remove the baking dish from the oven. Sprinkle the remaining one cup of shredded cheddar cheese evenly over the top of the hot casserole, covering the potato and ham mixture completely from edge to edge.
   Look for The surface is fully covered in cheese.
   Tip Freshly shredded cheese melts much better than pre-packaged cheese.
6. 6Broil to Golden Perfection
   Return the baking dish to the oven under the broiler. Broil for 3 to 5 minutes, watching very closely, until the cheddar cheese topping is completely melted, bubbling vigorously, and develops beautiful golden-brown spots. Remove from the oven and let rest for 5 minutes before serving.
   Look for The cheese is melted, bubbling, and golden brown.
   Tip Do not leave the oven unattended while broiling, as cheese burns quickly.

At the final checkpoint, the freshly added cheddar cheese on top should be completely melted, forming a beautiful, unbroken blanket across the entire casserole. The surface should feature deep golden-brown spots and active, sizzling bubbles under the broiler. When you lift a portion with a spatula, you should see an irresistible, stretchy cheese pull, with steam rising from the hot, creamy potato and ham layers beneath.

Common mistakes

One common mistake is cutting the potatoes into uneven or excessively large chunks, which results in some pieces remaining hard and undercooked while others turn mushy.

Another error is adding the topping cheese too early in the baking process; this causes the cheese to overcook, separate, and become greasy or burnt before the potatoes underneath have finished tenderizing. Always wait until the final minutes to add the top layer of cheese for that perfect, gooey melt.

How to tell it’s done

The casserole is fully done when the potatoes are tender throughout and the cheese on top is completely melted, bubbling, and beautifully browned.

Since the ham is already cooked, there is no raw meat to monitor, but the entire dish should be piping hot, reaching an internal temperature of at least 165°F (74°C) when tested with a food thermometer in the center. Let the casserole stand for a few minutes before serving to allow the sauce to set.