This oven baked 4-ingredients cheesy ham potato casserole is my no-fuss version of the dish my grandmother made every Easter with leftover ham. She’d slide a big glass baking dish into the oven, and the whole house would start to smell like melted cheese and crispy potatoes. It was the thing we all secretly looked forward to more than the ham itself. This simplified version keeps that same cozy, holiday feel, but it’s easy enough to throw together on a busy weeknight with just a few staples from the fridge and pantry.
Serve this casserole hot, straight from the glass baking dish while the cheese is still bubbly around the edges. It’s hearty enough to be the main dish, especially with a simple green salad or steamed green beans on the side to balance the richness. If you want to lean into the brunch-y Easter vibes, pair it with scrambled eggs and fresh fruit. A little hot sauce or a spoonful of sour cream on top is great for anyone who likes a bit of extra flavor, and warm dinner rolls or crusty bread are perfect for scooping up any cheesy bits from the corners of the pan.
Oven Baked Cheesy Ham Potato Casserole
Servings: 6

Ingredients
6 cups thinly sliced russet or Yukon Gold potatoes (about 2 pounds, peeled if desired)
2 cups cooked ham, diced (leftover Easter ham works perfectly)
3 cups shredded cheddar cheese, divided
2 cups whole milk (or 2% milk)
Directions
Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch glass baking dish so the potatoes and cheese don’t stick and the edges can crisp up nicely.
Layer half of the sliced potatoes evenly in the bottom of the prepared baking dish, spreading them out so they overlap slightly but don’t stack too thick in any one spot.
Sprinkle half of the diced ham evenly over the potatoes, then sprinkle 1 1/2 cups of the shredded cheddar cheese over the top of the ham.
Repeat the layers: add the remaining sliced potatoes in an even layer, then the rest of the ham, and finally another 1 1/2 cups of shredded cheddar cheese over the top, making sure to get cheese all the way to the edges for those crispy corners.
Slowly pour the milk evenly over the entire casserole, letting it seep down between the layers. Gently press down on the top with a spatula or clean hand to help the milk settle into the potatoes and ham without disturbing the layers too much.
Cover the baking dish tightly with foil and bake in the preheated oven for 45 minutes. This helps the potatoes cook through and the milk start to thicken without the cheese burning.
After 45 minutes, carefully remove the foil (watch for steam) and return the casserole to the oven, uncovered. Bake for another 25 to 35 minutes, or until the top is deep golden, the cheese is bubbling around the edges, and a knife slides easily through the center potatoes.
Once done, remove the casserole from the oven and let it rest for at least 10 to 15 minutes. This helps the cheesy, milky mixture thicken up so the slices hold together and you get that classic, cozy casserole texture.
Serve warm, scooping down to the bottom so everyone gets a bit of the crispy cheese edges, soft potatoes, and salty ham in each portion. Store any leftovers covered in the fridge and reheat in the oven or microwave until piping hot.
Variations & Tips
To keep the spirit of my grandmother’s Easter casserole, I like to use whatever leftover ham we have on hand, including the little end pieces that are a bit more flavorful. If you prefer, you can swap some or all of the cheddar for Colby Jack or a mild Swiss for a slightly different flavor. For extra richness, replace up to 1/2 cup of the milk with heavy cream, or for a bit of tang, use 1 cup milk and 1 cup half-and-half. If you want a little more seasoning without adding extra ingredients, use smoked ham or a sharper cheddar to boost flavor. You can also thinly slice the potatoes ahead of time and store them in cold water in the fridge for a few hours to make assembly even faster after work; just drain and pat dry before layering so the casserole doesn’t get watery. For a slightly crispier top, turn on the broiler for 1 to 2 minutes at the end of baking, watching closely so the cheese doesn’t burn. Food safety tips: Always start with fully cooked ham; if you’re using leftover Easter ham, make sure it has been refrigerated within 2 hours of serving and used within 3 to 4 days. Reheat leftovers to at least 165°F (74°C) before eating, and store them in an airtight container in the refrigerator for up to 3 days. If you prep the casserole ahead, keep it covered in the fridge for up to 24 hours, then bake until the center is hot and bubbly and the potatoes are tender, adding extra time as needed if it goes into the oven cold.