The Perfect Post-Christmas Comfort Food: Leftover Roast Potatoes with Homemade Cheese Sauce

After the whirlwind of Christmas feasting, the fridge is often packed with leftovers.

While the turkey, stuffing, and pigs in blankets are likely the stars of the show, there’s something magical about repurposing humble roast potatoes. 

Pair them with a luscious homemade cheese sauce, and you’ve got a dish that’s equal parts indulgent and comforting.

Here’s how to transform those crispy spuds into a post-Christmas treat that’s quick, easy, and oh-so-satisfying.

Why Roast Potatoes Deserve a Second Life

Roast potatoes are a staple of the British Christmas dinner, golden and crispy on the outside, fluffy on the inside. But reheating them can sometimes be tricky—no one wants soggy spuds. Pairing them with a creamy cheese sauce not only revives their flavour but elevates them into a rich and hearty snack or side dish.

The Recipe

Ingredients

For the cheese sauce:

25g (2 tbsp) butter

25g (2 tbsp) plain flour

300ml (1 ¼ cups) whole milk

100g (1 cup) mature cheddar cheese, grated

50g (½ cup) Parmesan cheese, grated (optional)

1 tsp Dijon mustard

A pinch of nutmeg (optional)

Salt and black pepper to taste

For the potatoes:

Leftover roast potatoes (as many as you like)

Olive oil (if reheating in the oven)

Method

Reheat the Roast Potatoes

Oven Method: Preheat your oven to 180°C (350°F). Spread the potatoes on a baking tray, drizzle with a little olive oil, and bake for 10–15 minutes until hot and crispy.

Air Fryer Method: Place the potatoes in an air fryer at 180°C for about 5–8 minutes.

Pan Method: Heat a non-stick pan over medium heat and fry the potatoes with a touch of oil until they regain their crispiness.

Make the Cheese Sauce

Melt the butter in a saucepan over medium heat. Add the flour and whisk continuously for 1–2 minutes to form a roux.

Gradually pour in the milk, whisking constantly to avoid lumps. Cook until the sauce thickens and coats the back of a spoon.

Stir in the cheddar cheese, Parmesan (if using), Dijon mustard, and a pinch of nutmeg. Season with salt and pepper to taste.

Serve

Pile the reheated roast potatoes onto a serving dish or individual bowls.

Generously drizzle the warm cheese sauce over the top.

For a festive touch, sprinkle with chopped chives, crispy bacon bits, or a dusting of smoked paprika.

Why You’ll Love This Dish

This recipe is the ultimate comfort food, perfect for lazy days between Christmas and New Year. The creamy cheese sauce adds richness, while the crispy potatoes bring texture and warmth. It’s a fantastic way to reduce food waste while treating yourself to something indulgent.

Customise It

Add Veggies: Toss in some leftover roasted Brussels sprouts, carrots, or parsnips for a colourful twist.

Spice It Up: Stir a pinch of chilli flakes or a dash of hot sauce into the cheese sauce for a kick.

Make It a Meal: Top with shredded leftover turkey or ham for a hearty dinner.

Whether you’re snuggled on the sofa with a good film or sharing a casual meal with family, this dish is sure to hit the spot. So, dig out those leftover spuds and whip up a batch of cheese sauce—you might just start a new post-Christmas tradition!

Happy feasting! (I ate this meal last night. Trust me, you will love it!_ 

Top Tips for Perfect Roast Potatoes for Your Christmas Dinner

There’s nothing quite like the golden crunch and fluffy interior of perfectly roasted potatoes to complete your Christmas dinner. 

Whether you're serving turkey, beef, or a vegetarian centrepiece, these humble spuds are often the star of the show. 

Here are some tips to ensure your roast potatoes steal the spotlight this Christmas.

1. Choose the Right Potato

The variety of potato you use is crucial. Opt for floury types like Maris Piper, King Edward, or Desiree. These varieties have a high starch content, which helps achieve that fluffy interior and crispy exterior.

2. Cut Them to the Right Size

Cut your potatoes into evenly sized chunks. Larger pieces give you a fluffy interior, while smaller ones crisp up faster. A mix of sizes can also work well if you want a variety of textures.

3. Parboil for Fluffiness

Parboiling is a non-negotiable step. Boil your potatoes in salted water for about 8-10 minutes, or until the edges start to soften. This softening helps create the rough, starchy surface that crisps up beautifully in the oven.

4. Rough Them Up

Once drained, give the potatoes a gentle shake in the pan or use a fork to rough up the edges. This step is key to creating those crispy, golden bits.

5. Choose the Right Fat

The fat you use can make or break your roasties. Goose fat or duck fat is traditional and delivers incredible flavour and crispness. For a vegetarian option, opt for a high-quality olive oil or rapeseed oil. Heat the fat in your roasting tin in a hot oven (around 200°C/400°F) before adding the potatoes.

6. Season Generously

Don’t skimp on seasoning. Sprinkle your potatoes with salt and pepper before roasting. For an extra touch of festive flavour, add garlic cloves, rosemary, or thyme to the tray.

7. Give Them Space

Crowding the tray is a common mistake. Ensure the potatoes have plenty of room to roast, not steam. Use two trays if necessary, as this allows the hot air to circulate and crisp up every side.

8. Turn Them Halfway

Turn the potatoes halfway through cooking to ensure even crisping. This also helps coat them in the hot fat for maximum crunch.

9. Cook at the Right Temperature

Roast your potatoes at a high temperature (around 200°C/400°F) for 45-60 minutes. Keep an eye on them towards the end to prevent burning and ensure they're perfectly golden.

10. Serve Immediately

Roast potatoes are at their best straight out of the oven. Serve them hot and crisp to ensure everyone enjoys them at their peak.

Bonus Tip: Make Ahead

If you’re juggling multiple dishes on Christmas Day, you can parboil and rough up your potatoes the day before. Store them in the fridge and roast them on the day for stress-free preparation.

By following these tips, your roast potatoes will be the talk of the table this Christmas. Whether you like them golden and crispy or with a hint of extra seasoning, these techniques will guarantee spud perfection. Happy roasting and Merry Christmas!