Ultimate Potato Casserole
This creamy, golden potato casserole features tender diced Russet or Yukon Gold potatoes in a rich, buttery cheese sauce, all topped with a bubbly cheddar crust and a crunchy corn flake or Panko topping. It's the ultimate comfort food side dish that's easy to make ahead and always earns recipe requests.
Equipment
- 9x13-inch baking dish - Ceramic or glass
- Large pot - For boiling potatoes
- Medium saucepan - For making cheese sauce
- Box grater - Or food processor with grating attachment
- Large mixing bowl
- Whisk
- Wooden spoon - Or silicone spatula
- Colander
- Cutting board
- Chef's knife
- Aluminum foil - For tenting if needed
Ingredients
- 3 lbs Russet or Yukon Gold potatoes - 1.4 kg, peeled and cut into 1-inch cubes
- 3 tbsp unsalted butter - 42g
- 1 medium yellow onion - finely diced
- 3 cloves garlic - minced
- 2 tbsp all-purpose flour - 16g
- 1 ½ cups whole milk - 360ml, warmed
- 1 cup sour cream - 240ml
- 2 ½ cups sharp cheddar cheese - 280g, freshly shredded, divided into 1 ½ cups and 1 cup
- 1 tsp garlic powder
- 1 tsp onion powder
- 1 tsp salt - plus more for boiling
- ½ tsp black pepper
- 6 slices thick-cut bacon - cooked and crumbled (optional)
- 3 green onions - scallions, thinly sliced, for topping
- nonstick cooking spray - for the baking dish
For the Crumb Topping
- 1 cup corn flake cereal - 30g, lightly crushed, or Panko breadcrumbs
- 2 tbsp unsalted butter - 28g, melted
Instructions
- Preheat oven to 375°F (190°C). Coat a 9x13 inch baking dish with nonstick spray.
- Peel and cut potatoes into 1-inch cubes. Boil in salted water for 10-12 minutes until just fork-tender. Drain and steam dry for 2-3 minutes.
- Cook bacon in a skillet over medium-low heat until crispy. Drain on paper towels, crumble, and set aside.
- In a saucepan, melt butter over medium heat. Sauté onion for 3-4 minutes until softened. Add garlic and cook 1 minute until fragrant.
- Stir in flour and cook for 1-2 minutes. Gradually whisk in warm milk, stirring constantly, until the sauce thickens, about 3-4 minutes.
- Remove from heat and stir in sour cream, 1 ½ cups of cheddar cheese, garlic powder, onion powder, salt, and pepper until smooth and creamy.
- Combine the drained potatoes with the cheese sauce in a large bowl. Fold in half the crumbled bacon. Transfer to the prepared baking dish.
- Mix crushed cereal or Panko with melted butter. Sprinkle the remaining 1 cup of cheddar, remaining bacon, and buttered crumb topping over the casserole.
- Bake uncovered for 25-30 minutes until golden and bubbling. Tent with foil if browning too quickly. Rest for 5 minutes before serving.
- Garnish with sliced green onions and serve hot directly from the baking dish.
Notes
- Grate your own cheese: Pre-shredded cheese contains anti-caking agents that prevent smooth melting. Freshly grated block cheese makes a superior, silky sauce.
- Don't overboil potatoes: They should be just barely fork-tender, as they will finish cooking in the oven. Overcooked potatoes become mushy.
- Warm the milk: Adding cold milk to a hot roux can cause lumps. Warm the milk for about 30 seconds in the microwave before adding.
- Dry potatoes thoroughly: Let them steam dry after draining to avoid a watery casserole. Excess moisture dilutes the sauce.
- Make ahead: Assemble the casserole completely (without the crumb topping) up to two days in advance. Cover and refrigerate. Add topping just before baking and add 10-15 minutes to bake time.
- Frozen hash brown shortcut: Substitute 2 lbs (900g) of thawed and drained frozen shredded hash browns for fresh potatoes. Skip the boiling step entirely.
- Variations: Try adding diced cooked ham, diced jalapeños, or broccoli florets. For a lighter version, use plain Greek yogurt instead of sour cream.
- Storage: Leftovers keep in the refrigerator for up to 4 days. Reheat covered in a 350°F oven for 20-25 minutes, or in the microwave with a splash of milk.
- Freezing: Assemble the casserole without the crumb topping, cool completely, and freeze for up to 3 months. Thaw overnight in the fridge before adding topping and baking.
- Let it rest: Allow the casserole to rest for at least 5 minutes before serving. This helps the sauce settle for cleaner portions.