Print

Mashed Potato Casserole Recipe

Print Recipe

★★★★★

4.7 from 136 reviews

This Mashed Potato Casserole is a comforting and cheesy dish featuring tender, creamy mashed potatoes layered with crispy bacon and melted mozzarella and cheddar cheeses. Perfect as a hearty side or a satisfying main, this recipe offers flexibility with make-ahead instructions and is finished with fresh green onions for a bright, savory touch.

Ingredients

Scale

Potatoes and Dairy

  • 0.17 kg (0.35 lb) potatoes (Sebago (Aus), Russet (US), Maris Piper / King Edwards (UK))
  • 0.1 tbsp cooking or kosher salt, for cooking potatoes
  • 0.07 cup whole milk (preferably full fat, lite is acceptable)
  • 0.07 cup extra milk (for make-ahead option only)
  • 7.5 g (0.5 tbsp) unsalted butter, cut into 1 cm (1/2″) cubes
  • 0.05 cup sour cream or full-fat yogurt
  • 0.1 tsp cooking or kosher salt, or to taste

Cheese and Toppings

  • 0.15 cups (tightly packed) shredded mozzarella cheese
  • 0.1 cup (tightly packed) shredded Red Leicester, cheddar, or other flavored cheese
  • 20 g (0.6 oz) streaky bacon, chopped
  • 0.03 cup finely sliced green onion

Instructions

  1. Cook bacon: Place chopped bacon in a cold non-stick pan over medium heat without adding oil. As the pan heats up, the bacon fat will render. Once you see the melted fat, increase heat to medium-high and stir continuously for about 3 minutes or until the bacon turns golden and crispy. Remove the bacon and drain on paper towels to remove excess fat.
  2. Prepare potatoes: Peel the potatoes and cut them into 3 cm (1 inch) chunks. Place them in a large pot and cover with water so it is 10 cm (4 inches) above the potatoes. Add 1 tablespoon of salt to the water.
  3. Boil potatoes: Bring the pot to a boil over high heat, then reduce to a rapid simmer. Cook the potatoes for about 15 minutes or until they are very soft and easily pierced with a fork. Drain the potatoes well and return them to the pot. Leave them for 1 minute, shaking occasionally to help evaporate excess water.
  4. Mash potatoes: Add the milk (include the extra milk if using the make-ahead option), butter cubes, sour cream, and 1 teaspoon salt to the potatoes. Mash thoroughly using a hand masher until smooth. Avoid using a food processor, blender, or electric beater as this can make the potatoes gluey.
  5. Make-ahead instructions: If you want to prepare this ahead of time, allow the mashed potatoes to cool completely at room temperature. Cover tightly with cling film and refrigerate. When ready to bake, remove from the fridge and sit on the counter for 2 hours to come to room temperature before proceeding.
  6. Assemble casserole: Preheat the oven to 200°C (400°F) or 180°C fan. Transfer the mashed potatoes to a 2 litre (2 quart) baking dish and smooth the surface evenly. Sprinkle the shredded mozzarella and cheddar (or other flavoured cheese) evenly over the top, followed by the cooked bacon.
  7. Bake covered: Loosely cover the dish with foil. Bake for 20 minutes if freshly made or 35 minutes if using the make-ahead option.
  8. Bake uncovered: Remove the foil and bake for an additional 10 minutes until the cheeses are bubbly and golden brown on top.
  9. Serve: Sprinkle the finely sliced green onions over the casserole and serve immediately. The dish retains heat well for about 20 minutes due to the protective cheese layer.

Notes

  • Choose starchy potatoes like Russet, Sebago, Maris Piper, or King Edward for the best mash texture.
  • Use full-fat milk and sour cream for creamier, richer mashed potatoes.
  • If making ahead, the extra 0.07 cup milk is added during mashing to keep the potatoes creamy after refrigeration.
  • Bacon adds a salty, crispy contrast; streaky bacon is recommended for flavor and fat content.
  • The baking dish should be around 2 liters (2 quarts) to accommodate the potato volume comfortably.
  • Do not overmix potatoes with electric appliances to avoid gummy texture.

Keywords: mashed potatoes, potato casserole, cheesy potato bake, bacon mashed potatoes, comfort food, side dish

Find it online: https://kitchenwithkai.com/mashed-potato-casserole-recipe/