Make a creamy and cheesy scalloped potatoes casserole with layers of tender red potatoes, cooked ham, caramelized onions, and a rich homemade cheese sauce. Baked until golden and bubbling, this hearty dish is ideal for family dinners, holidays, or as a filling side dish. Made with cheddar, Gruyère, and Red Leicester, it’s a popular comfort food recipe that’s easy to prepare in the oven.

This comforting casserole combines tender layers of sliced red potatoes, savory ham, sweet caramelized onions, and a rich, creamy cheese sauce. Baked until golden and bubbling, it’s the perfect hearty dish for a cozy family dinner or a satisfying side for gatherings.

Ingredients

For the Filling

2 tbsp unsalted butter
1 large onion, thinly sliced
2 cloves garlic, minced
½ tsp salt (divided)
½ tsp black pepper (divided)
¼ tsp garlic salt
200 g (7 oz) cooked ham, cubed
4 red-skinned potatoes*, peeled and thinly sliced

For the Cheese Sauce

4 tbsp unsalted butter
6 tbsp all-purpose flour
560 ml (2 ⅓ cups) whole milk
180 ml (¾ cup) heavy (double) cream
150 g (1 ½ packed cups) mature cheddar, grated
50 g (½ packed cup) Gruyère cheese, grated
50 g (½ packed cup) Red Leicester cheese, grated
1 tbsp chopped fresh thyme (for garnish)

Instructions

Preheat the oven
Set your oven to 180°C (350°F) fan. Lightly grease a large casserole or baking dish.
Sauté the aromatics
Melt 2 tbsp butter in a skillet over medium-high heat. Add the sliced onion, minced garlic, ¼ tsp salt, ¼ tsp black pepper, and garlic salt. Cook for 5–6 minutes, stirring often, until softened. Remove from heat.
Prepare the cheese sauce
In a medium saucepan, melt 4 tbsp butter over medium-high heat. Whisk in the flour and cook for 1 minute, stirring continuously. Gradually add the milk, a splash at a time, whisking to avoid lumps. Once smooth, stir in the cream and ¾ of the cheddar. Cook until the cheese has melted into a smooth sauce.
Assemble the layers
Layer half of the sliced potatoes in the base of the dish. Top with half the sautéed onion and half of the cubed ham. Sprinkle with ¼ tsp each of salt and pepper. Pour over half the cheese sauce. Repeat with the remaining potatoes, onion, ham, seasoning, and sauce.
Add the final cheeses
Sprinkle the top with the remaining cheddar, the Gruyère, and Red Leicester.
Bake
Cover tightly with foil and bake for 75–90 minutes, or until the potatoes are tender when pierced with a knife. Remove the foil and bake for an additional 15–20 minutes until the top is golden and bubbling.
Serve
Let the dish rest for 5 minutes before serving. Garnish with fresh thyme.

Tips

Slice potatoes evenly: This ensures uniform cooking. Use a mandoline if you have one.
Test doneness: A sharp knife should slide easily through the layers without resistance.
Rest before serving: A short resting period allows the sauce to thicken slightly.

Variations and Substitutions

Cheese swaps: Use mozzarella or Monterey Jack in place of Red Leicester or Gruyère.
Vegetarian version: Omit the ham and add sautéed mushrooms or spinach instead.
Milk alternatives: Whole milk works best, but semi-skimmed can be used for a lighter version.

FAQs

Can I make this ahead of time?
Yes. Assemble the dish, cover, and refrigerate for up to 24 hours. Add 10–15 minutes to the baking time if baking straight from the fridge.

Can I freeze leftovers?
Yes, cool completely, portion, and freeze for up to 2 months. Reheat in the oven or microwave until piping hot.

Can I use other types of potatoes?
Yes, Yukon Gold or russet potatoes also work well. Just avoid waxy varieties that don’t soften easily.

Serving Suggestions

Serve as a main dish with a simple green salad or steamed vegetables.
Makes a rich and hearty side for roast chicken, pork, or glazed ham.
Great for brunch alongside eggs or as part of a festive buffet.

Why You’ll Love This Recipe

Creamy, cheesy, and deeply comforting
Simple ingredients, big flavor
Perfect for holidays, family dinners, or potlucks
Customizable and freezer-friendly