Description
A creamy, comforting Cheesy Onion Mashed Potato Casserole layered with fluffy russet potatoes, sweet caramelized onions, and golden melted cheddar cheese, baked until perfectly bubbly and lightly crisp on top.
Ingredients
Units
Scale
- 3 pounds russet potatoes, peeled and cut into chunks
- 2 medium yellow onions, thinly sliced
- 2 cups shredded cheddar cheese
- 4 tablespoons unsalted butter
- 1 cup whole milk, warmed
- 1 cup sour cream
- 1 teaspoon salt, or to taste
- 1/2 teaspoon black pepper
Instructions
- Preheat the oven to 375 degrees Fahrenheit.
- Bring a large pot of salted water to a boil. Add the potatoes and cook for 15 to 20 minutes until fork tender. Drain thoroughly.
- Mash the hot potatoes with butter, warm milk, sour cream, salt, and black pepper until smooth and creamy.
- Lightly grease a 9×13 inch baking dish with butter.
- Spread half of the mashed potatoes into the prepared dish.
- In a skillet over medium heat, sauté the sliced onions for about 10 minutes until soft and golden.
- Layer the sautéed onions over the potatoes and sprinkle with 1 cup of shredded cheddar cheese.
- Spread the remaining mashed potatoes on top and finish with the remaining 1 cup of cheddar cheese.
- Bake uncovered for 20 to 25 minutes until the cheese is melted and lightly golden.
- Let rest for 5 to 10 minutes before serving.
Notes
- Warm the milk before mixing to keep the potatoes fluffy.
- Do not overmix the potatoes to avoid a dense texture.
- The casserole can be assembled one day ahead and refrigerated before baking.
Nutrition
- Serving Size: 1 serving
- Calories: 380
- Sugar: 4g
- Sodium: 420mg
- Fat: 22g
- Saturated Fat: 13g
- Unsaturated Fat: 7g
- Trans Fat: 0g
- Carbohydrates: 36g
- Fiber: 3g
- Protein: 10g
- Cholesterol: 60mg