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!_