Creamy, buttery, cheesy mashed potato loaded with crispy bacon and finished with caramelised onions, more melted cheese and crunchy bacon bits. It’s pure comfort food—and it can be made up to two days ahead and reheated for an elegant side dish. Ideal for Thanksgiving or Christmas.
If you thought mashed potato couldn’t get any better, add cheese, caramelised onions and crispy bacon. The result is rich, indulgent and irresistible—often enjoyed straight from the oven.
Table of Contents
- 📋 Ingredients
- How to make it:
- Pro Tip
- 🍽️ What to serve it with
- 🍲 More fantastic side dishes
- ? Frequently Asked Questions
- Make Ahead Mashed Potato Casserole with Bacon Recipe
📋 Ingredients
Potatoes – use floury varieties (Maris Piper, King Edward, Russet, Yukon Gold or similar) for fluffy mash.
Cheese – a mix of Cheddar and Red Leicester works beautifully, but use any melting cheese you prefer.
How to make it:
Full recipe with exact quantities and timings is in the recipe card at the end of this post.
- Peel and boil the potatoes until tender. While they cook, fry the bacon until crisp and chop into small pieces.
- Drain and mash the potatoes until smooth. Stir in butter, cream and milk, season with salt and pepper, then fold through most of the cheese and three-quarters of the bacon. Transfer into a large, shallow baking dish.
- Using the pan you cooked the bacon in, fry the onions in the bacon fat with a little butter until soft and golden.
- Spoon the onions over the mash, sprinkle with the remaining cheese and cover with foil. Bake until heated through, then remove the foil, scatter the remaining bacon over the top and bake briefly until the cheese is golden and bubbling.
- Top with sliced spring onions (scallions) and serve.
Pro Tip
If you prefer, use frozen mashed potato pellets to save time—see the notes for guidance and food-safety advice.
When it comes to bacon, add as much as you like—this dish rewards generosity.
Pin this now to find it later
🍽️ What to serve it with
This casserole makes a superb side for festive meals. Pair it with roast turkey, nut roast, pigs in blankets or rich gravy for a satisfying spread.
🍲 More fantastic side dishes
Sauces and Dips
Make Ahead Gravy for Christmas
Sides
Honey Roasted Carrots
Sauces and Dips
Cranberry Sauce with Port
Sides
Honey Roasted Parsnips
Roast Dinner
The Best Crispy Roast Potatoes
Roast Dinner
The Best Yorkshire Pudding Recipe
? Frequently Asked Questions
Yes. Prepare the bake up to two days in advance, cool completely, cover and refrigerate. Reheat according to the recipe card instructions so it warms through evenly.
Yes, frozen mashed potato pieces are a useful shortcut if you plan to cook and serve immediately. They’re already cooked, so avoid reheating, cooling and reheating again for food safety reasons. If using pellets, follow the pack directions and then mix in butter, cream and seasoning before finishing the recipe.
Stay updated with new recipes! Subscribe to the newsletter to get new posts and follow along on social channels for videos and behind-the-scenes content.
Make Ahead Mashed Potato Casserole with Bacon
Equipment
- Potato ricer (optional, for extra-smooth mash)
Ingredients
Mashed Potato:
- 1.5 kg (3.3 lb) floury potatoes, chopped into even chunks
- 80 g (1/3 cup) unsalted butter
- 80 ml (1/3 cup) double (heavy) cream
- 60 ml (1/4 cup) full-fat milk
- 1/2 tsp table salt
- 1/2 tsp black pepper
- 75 g (3/4 packed cup) mixed grated cheese (Cheddar & Red Leicester suggested)
Onion, bacon and cheese toppings:
- 1 tbsp oil
- 200 g (7 oz) smoked bacon rashers, fried and chopped
- 30 g (2 tbsp) unsalted butter
- 2 medium onions, thinly sliced
- 1/2 tsp salt
- 1/2 tsp black pepper
- 150 g (1 1/2 packed cups) mixed grated cheese
To Serve:
- 3 tbsp finely sliced spring onions (scallions)
Instructions
Boil the potatoes:
- Place the potatoes in a pan, cover with cold water and bring to the boil. Simmer for 15–20 minutes until tender when pierced with a knife. Avoid overcooking to prevent watery mash.
Bacon:
- Heat oil in a large frying pan and cook the bacon in a single layer until crisp, about 6–7 minutes. Remove, chop and reserve. Keep the pan (don’t wash) for flavour.
Make the cheesy mashed potatoes:
- Drain the potatoes and let them sit briefly so excess moisture evaporates. Rice or mash the potatoes until smooth.
- Stir in the butter so it melts, then add the cream, milk, salt and pepper and mix until creamy. Fold in the cheese and three-quarters of the chopped bacon. Spoon into a shallow baking dish (no deeper than 5 cm/2″).
Fry the onions:
- Add butter to the frying pan with the bacon fat, then fry the sliced onions for 8–10 minutes until softened and slightly browned. Preheat the oven to 180°C/375°F (fan).
Assembly and baking:
- Spoon the onions over the mash, sprinkle with the remaining cheese and cover with foil. Bake for 20 minutes.
- Remove the foil, scatter the remaining bacon on top and return to the oven for 5–10 minutes until golden and bubbling. Serve topped with spring onions.
If making ahead:
- After adding the onions and cheese, cool the dish completely, cover with foil and refrigerate for up to two days. Store remaining cooked bacon separately.
- Take the casserole from the fridge about 2 hours before reheating so it comes closer to room temperature. Preheat the oven to 180°C/375°F (fan).
- Bake covered for 45 minutes, then remove the foil, scatter the reserved bacon and bake uncovered for a further 5–10 minutes until hot and golden.
Notes
Potato variety
Choose floury potatoes such as Maris Piper, King Edward, Russet or Yukon Gold for the best texture.
Chopping the potatoes
Cut into medium, even-sized chunks so they cook evenly—about the size of half a kiwi fruit.
Frozen mashed potato pellets option
Frozen mashed potato pieces are a good shortcut if cooking and serving straight away. Use about 1.8 kg (4 lb) frozen mash and follow pack instructions, then mix in butter, cream and seasoning before finishing the recipe. Do not use this method if you plan to make, chill and reheat later for food-safety reasons.
Nutritional information shown in the recipe card is approximate per serving.
Nutrition
Nutrition figures are estimates.
Some links in this post may be affiliate links; if you purchase through them I may earn a small commission at no extra cost to you. Nutrition information is approximate; see site terms for details.