Cheesy Scalloped Potatoes and Ham

Ingredients

• 6 mediumYukon Gold potatoes
• 57 g (4 tablespoons)butter
• 1yellow onion, sliced into thin strips
• 3 clovesgarlic, minced
• 30 g (¼ cup)plain flour
• 355 ml (1½ cups)half-and-half or milk
• ¾ teaspoondried rosemary
• ½ teaspoon eachdried oregano, thyme and sage
• 200 g (2 cups)cheddar, grated; reserve ½ cup to top the casserole
• 50 g (½ cup)Gruyère, grated
• 1 cupcooked ham, diced
• 25 g (¼ cup)Parmesan, freshly grated
• 1 tablespoonfresh parsley, roughly chopped

Instructions

1. 1

   Prepare the cheese

   Grate the cheddar and Gruyère and set them aside to come close to room temperature. Keep ½ cup of the cheddar back for the topping.

2. 2

   Cook the onions

   Melt the butter in a medium saucepan over medium heat. Add the sliced onion and cook for 20 minutes or longer, stirring now and then, until it begins to brown and caramelise.

3. 3

   Make the sauce

   Stir in the minced garlic and cook for 1 minute. Add the flour gradually, stirring constantly to make a paste, then cook for 1 minute.

4. 4

   Add the milk

   Warm the half-and-half or milk in the microwave for 30 seconds. Pour it into the saucepan and stir to combine.

5. 5

   Season and simmer

   Add the rosemary, oregano, thyme and sage. Simmer for 5 minutes, then take the pan off the heat.

6. 6

   Finish the sauce

   Gradually stir in 1½ cups of the cheddar and all the Gruyère until the sauce is smooth. Mix in the diced ham; reserve some for the topping if you like.

7. 7

   Heat the oven

   Preheat the oven to 200°C (400°F).

8. 8

   Slice the potatoes

   Peel the potatoes and slice them about 3 mm (⅛ inch) thick. A mandoline can make slicing easier.

9. 9

   Layer the casserole

   Lightly grease a 23 x 33 cm (9 x 13 inch) casserole dish. Arrange one-third of the potatoes in a single, overlapping layer on the bottom; season lightly with salt and pepper if desired.

10. 10

    Add the sauce

    Spoon one-third of the cheese sauce over the potatoes and use a pastry brush to coat them completely. Repeat the potato and sauce layers twice, using all the potatoes and sauce.

11. 11

    Add the topping

    Scatter the reserved cheddar and any reserved diced ham over the top.

12. 12

    Bake covered

    Cover the casserole and bake for 30 minutes.

13. 13

    Pause if needed

    For make-ahead preparation, let the casserole cool completely, then refrigerate or freeze it until ready to serve.

14. 14

    Uncover and top

    Remove the cover and add the finely grated Parmesan. Reduce the oven temperature to 190°C (375°F).

15. 15

    Finish baking

    Bake for a further 25 minutes, until the cheese is hot and bubbling and begins to brown.

16. 16

    Rest and serve

    Top with chopped parsley and leave the casserole to stand for 5 minutes before serving.

What are scalloped potatoes?

Scalloped potatoes are thinly sliced potatoes baked in layers with a creamy sauce. This version adds cooked ham and two cheeses, making it a substantial casserole that can be served as a side or a main dish.

The dish belongs to a broad tradition of baked potato casseroles rather than one single fixed recipe. Here, a flour-thickened sauce, sweet caramelised onion and a Parmesan topping give the layers richness and a browned finish.

Nutrition and macros by portion

The nutrition label shows one serving as written: 405 calories, 18g protein, 30g carbs, 25g fat.

Potatoes provide most of the carbohydrates, while butter, half-and-half and cheese contribute much of the fat. Ham and the cheeses supply protein; serve a portion with green vegetables or salad for a more balanced plate.

Build flavour in the sauce

Onions: Give them the full 20 minutes, or longer if needed, to soften and begin to caramelise. Stir occasionally so they cook evenly without catching.

Cheese: Let the grated cheddar and Gruyère come close to room temperature, then stir them into the sauce off the heat. This helps them melt into a smooth mixture.

Slice for even cooking

Potatoes: Aim for slices about 3 mm thick so the layers cook at a similar rate. A mandoline is handy, but a sharp knife works if you keep the slices even.

Layers: Arrange the slices with a slight overlap and spread sauce across them. Coating the exposed potato helps limit discolouration while you assemble the casserole.

Look for the right finish

Sauce: After the cheese is added, it should be smooth and thick enough to cling to a spoon. Take the pan off the heat before adding the cheese to reduce the risk of a grainy texture.

Top: The casserole is ready when the cheese is bubbling and beginning to brown. Rest it for 5 minutes before serving so the layers settle slightly.

Plan the cooking time

Onions: The sauce starts with at least 20 minutes of onion cooking, followed by the other sauce stages. Allow time for this before assembling the dish.

Oven: The stated baking stages add up to 55 minutes: 30 minutes covered, then 25 minutes uncovered at the lower temperature. The listed 50-minute total does not include all of those stages.

Make it ahead and serve

Make ahead: The recipe suggests cooling the casserole completely before refrigerating or freezing it. If it is cold when it goes into the oven, allow extra time and check that the centre is hot before serving.

Serve with: Pair it with a green salad or simply cooked green vegetables to offset the creamy, savoury layers. It also works alongside roast meat.

Recipe notes & tips

• Grate the cheese before starting the sauce so it is ready to stir in.
• Keep the onions over medium heat and stir occasionally while they soften and brown.
• Slice the potatoes evenly so they cook through at roughly the same time.
• Brush sauce over the potato layer rather than leaving slices exposed.
• If you reserve ham for the top, keep it separate until assembly.
• Let the finished casserole rest for 5 minutes before cutting into it.

Variations

• Use milk: Swap the half-and-half for milk for a less rich sauce.
• Change the cheese: Use another good-melting cheese in place of Gruyère.
• Add mustard: Stir a little mustard into the sauce for a sharper savoury note.
• Add greens: Layer in cooked spinach between the potatoes and sauce.
• Make it meat-free: Leave out the ham and serve the casserole as a cheesy potato side.

Common mistakes to avoid

• Rushing the onions: They need at least 20 minutes to begin browning; keep cooking and stirring occasionally.
• Adding cheese over high heat: The sauce can turn grainy; take it off the heat before stirring in the cheese.
• Uneven potato slices: Thick slices may stay firm while thin ones soften; aim for an even 3 mm thickness.
• Leaving potatoes uncovered in the layers: Brush sauce over the slices to coat them completely.
• Skipping the final uncovered bake: Remove the cover for the last 25 minutes so the cheese can bubble and brown.
• Cutting it straight from the oven: Give the casserole its 5-minute rest so the layers settle.

How to store

Cool the casserole completely, then cover and refrigerate or freeze it, as the recipe suggests. Reheat until piping hot throughout; allow extra time if reheating from chilled or frozen.

Frequently asked questions