Walla Walla Onion Casserole
Indulge in the comforting, savory flavors of a Walla Walla Onion Casserole, a creamy and cheesy baked dish that celebrates the natural sweetness of Walla Walla onions. This delightful recipe features tender caramelized onion rings layered beneath a rich, velvety cheddar and Parmesan cheese sauce, all crowned with a crispy, golden panko breadcrumb topping. Perfect as a side dish or a warm, filling centerpiece, this casserole is easy to assemble with a straightforward roux-based sauce and just the right blend of wholesome ingredients. Ready in under an hour, it’s ideal for family dinners, potlucks, or holiday gatherings. Garnish with fresh parsley for a pop of color, and enjoy a dish that's as comforting as it is delectable!
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Recipe Information
Ingredients
- 4 large Walla Walla onions
- 4 tablespoons unsalted butter
- 3 tablespoons all-purpose flour
- 2 cups whole milk
- 1 cup heavy cream
- 1.5 cups shredded cheddar cheese
- 0.5 cups grated Parmesan cheese
- 1 teaspoon salt
- 0.5 teaspoons black pepper
- 1 cup panko breadcrumbs
- 1 tablespoon olive oil
- 2 tablespoons fresh parsley (optional, for garnish)
Instructions
Preheat your oven to 375°F (190°C). Grease a 9x13-inch casserole dish lightly with butter or cooking spray and set aside.
Peel and thinly slice the Walla Walla onions into rings. Set aside.
In a large skillet, melt 2 tablespoons of butter over medium heat. Add the sliced onions and cook for 10-12 minutes, stirring occasionally, until the onions are soft and just starting to caramelize. Remove from heat.
In a medium saucepan, melt the remaining 2 tablespoons of butter over medium heat. Once melted, whisk in the flour to form a roux and cook for 1-2 minutes until lightly golden.
Gradually pour in the milk and heavy cream, whisking constantly to ensure no lumps form. Cook for 3-4 minutes until the mixture thickens.
Stir in the shredded cheddar cheese and Parmesan cheese until melted and smooth. Season with salt and black pepper, then remove from heat.
Layer the cooked onions in the prepared casserole dish. Pour the cheese sauce evenly over the onions, ensuring all are well coated.
In a small bowl, combine the panko breadcrumbs with the olive oil, mixing gently until the breadcrumbs are evenly coated. Sprinkle the breadcrumb mixture evenly over the top of the casserole.
Bake the casserole in the preheated oven for 20-25 minutes, or until the top is golden brown and bubbling.
Remove the casserole from the oven and let it rest for 5 minutes before serving. Garnish with chopped fresh parsley, if desired.
Nutrition Facts
Calories |
561 | ||
|---|---|---|---|
% Daily Value* |
|||
| Total Fat | 37.7 g | 48% | |
| Saturated Fat | 22.4 g | 112% | |
| Polyunsaturated Fat | 0.0 g | ||
| Cholesterol | 106 mg | 35% | |
| Sodium | 823 mg | 36% | |
| Total Carbohydrate | 38.1 g | 14% | |
| Dietary Fiber | 3.1 g | 11% | |
| Total Sugars | 15.3 g | ||
| Protein | 16.9 g | 34% | |
| Vitamin D | 1.1 mcg | 6% | |
| Calcium | 432 mg | 33% | |
| Iron | 1.6 mg | 9% | |
| Potassium | 444 mg | 9% | |
*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
