Description
This Mashed Potato Casserole is a comforting and cheesy baked dish featuring creamy mashed potatoes layered with melted mozzarella, flavorful cheddar, crispy bacon, and topped with fresh green onions. Ideal for busy weeknights or make-ahead meals, this casserole combines smooth, fluffy potatoes with savory cheese and bacon for a crowd-pleasing side or main dish.
Ingredients
Scale
Potatoes and Cooking
- 1.75kg / 3.5 lb potatoes (Sebago, Russet, Maris Piper, or King Edwards)
- 1 tbsp cooking/kosher salt (for cooking potatoes)
Milk and Dairy
- 2/3 cup milk (preferably full fat/whole milk)
- 2/3 cup extra milk (for make-ahead option only)
- 75g / 5 tbsp unsalted butter, cut into 1cm / 1/2″ cubes
- 1/2 cup sour cream (full fat preferred)
Cheeses
- 1 1/2 cups shredded mozzarella (tightly packed)
- 1 cup shredded Red Leicester, cheddar, or other flavored cheese (tightly packed)
Other
- 1 tsp cooking/kosher salt (or to taste)
- 200g / 6 oz streaky bacon, chopped
- 1/4 cup green onion, finely sliced
Instructions
- Cook Bacon: Place the chopped streaky bacon in a cold non-stick pan over medium heat without adding oil. As the pan warms, the bacon fat will begin to melt. Once you see some melted fat, increase the heat to medium-high and stir frequently for about 3 minutes or until the bacon turns golden and crisp. Drain the cooked bacon on paper towels to remove excess fat.
- Prepare Potatoes: Peel the potatoes and cut them into 3cm (1 inch) chunks. Place them in a large pot and cover with cold water so that the water level is about 10cm (4 inches) above the potatoes. Add 1 tablespoon of kosher salt to the water.
- Cook Potatoes: Bring the pot to a boil over high heat, then reduce to a rapid simmer. Cook for approximately 15 minutes or until the potatoes are very soft and easily pierced with a fork.
- Drain and Mash: Drain the potatoes thoroughly and return them to the pot. Allow them to sit for 1 minute, shaking the pot occasionally to help evaporate any residual water. Add milk (including extra milk if using the make-ahead option), butter, sour cream, and 1 teaspoon salt. Mash using a potato masher until smooth. Avoid using a food processor or blender as these can make the potatoes gluey.
- Make-Ahead Option: Allow the mashed potatoes to cool fully at room temperature. Cover tightly with cling wrap and refrigerate. Before reheating, remove from the fridge 2 hours prior to allow it to come to room temperature evenly.
- Assemble Casserole: Preheat the oven to 200°C (400°F) or 180°C for fan ovens. Spread the mashed potato evenly into a 2 litre (2 quart) baking dish, smoothing the surface carefully.
- Add Toppings: Sprinkle the shredded mozzarella and cheddar cheese evenly over the mashed potatoes, then distribute the cooked bacon on top.
- Bake Covered: Cover the dish loosely with foil and bake. For freshly made mash, bake for 20 minutes. For make-ahead refrigerated mash, bake for 35 minutes to ensure thorough heating.
- Bake Uncovered: Remove the foil and bake for an additional 10 minutes until the cheese is bubbly and golden brown.
- Serve: Sprinkle finely sliced green onions over the top and serve hot. The casserole will remain warm for about 20 minutes due to the cheese layer, making it perfect for serving gatherings or family meals.
Notes
- Potatoes: Use any starchy or all-purpose potato variety suitable for mashing such as Sebago, Russet, Maris Piper, or King Edwards.
- Extra Milk: Adding extra milk in make-ahead mash keeps the texture loose after refrigeration and reheating, maintaining creaminess.
- Cheese: Use freshly shredded mozzarella for excellent melting quality paired with Red Leicester or cheddar for flavor and color. Avoid pre-shredded cheese as it contains anti-caking agents that inhibit melting.
- Bacon: Use streaky or fatty bacon so it can be cooked without additional oil. Lean bacon will require oil to prevent sticking.
- Dish Size: A 2 litre (2 quart) baking dish is ideal and will be filled to the brim. A 23 x 33cm (9 x 13 inch) dish (3 litre / 3 quart) can also be used but will be about two-thirds full.
- Make-Ahead Storage: The assembled casserole can be kept in the refrigerator for up to 3 days uncooked (excluding green onions). Bring to room temperature before reheating for even cooking.
- Freezing: The assembled dish freezes well when thawed and reheated, though this is based on anecdotal evidence from previous users.
- Leftovers: Keep refrigerated for up to 3 days. The mash may lose creaminess, so consider repurposing leftovers into mashed potato cakes.
Nutrition
- Serving Size: 1/12 of casserole
- Calories: 320 kcal
- Sugar: 2 g
- Sodium: 520 mg
- Fat: 18 g
- Saturated Fat: 9 g
- Unsaturated Fat: 7 g
- Trans Fat: 0 g
- Carbohydrates: 28 g
- Fiber: 3 g
- Protein: 12 g
- Cholesterol: 50 mg
