Rich, creamy, and irresistibly comforting, Nettie's Onion Casserole takes humble sweet onions and transforms them into a show-stopping dish bursting with flavor. Featuring tender, caramelized Vidalia onions enveloped in a velvety cheddar cheese sauce and topped with a golden breadcrumb-Parmesan crust, this casserole is the perfect blend of creamy and crunchy textures. With just 20 minutes of prep time, it’s a quick and easy recipe that's ideal for holidays, potlucks, or weeknight dinners. Serve it as a decadent side dish or let it shine as a comforting vegetarian main. Your kitchen will be filled with the irresistible aroma of bubbling cheese and toasty breadcrumbs—this is a recipe your family and guests will beg you to make again and again.
Preheat your oven to 375°F (190°C). Grease a 9x13-inch casserole dish and set it aside.
Peel and slice the onions into thin rings. In a large skillet, melt 2 tablespoons of butter over medium heat and sauté the onions for 10-12 minutes, stirring occasionally, until they are soft and lightly golden. Set aside.
In a medium saucepan, melt the remaining 2 tablespoons of butter over medium heat. Add the flour and whisk continuously for 1-2 minutes to create a roux.
Slowly pour in the milk, whisking constantly, and cook for 3-4 minutes until the mixture thickens into a creamy sauce.
Remove the saucepan from heat and stir in the shredded cheddar cheese, sour cream, salt, and black pepper until smooth.
Add the sautéed onions to the cheese mixture and mix gently to coat the onions evenly.
Pour the onion and cheese mixture into the prepared casserole dish and spread it evenly.
In a small bowl, mix together the breadcrumbs, grated Parmesan cheese, and olive oil until combined. Sprinkle the breadcrumb mixture evenly over the casserole.
Bake the casserole in the preheated oven for 25-30 minutes, or until the top is golden and bubbling.
Let the casserole cool for 5-10 minutes before serving. Enjoy warm as a side dish or main course.
Calories |
2476 | ||
|---|---|---|---|
% Daily Value* |
|||
| Total Fat | 150.7 g | 193% | |
| Saturated Fat | 84.8 g | 424% | |
| Polyunsaturated Fat | 1.9 g | ||
| Cholesterol | 404 mg | 135% | |
| Sodium | 6048 mg | 263% | |
| Total Carbohydrate | 204.0 g | 74% | |
| Dietary Fiber | 18.3 g | 65% | |
| Total Sugars | 71.0 g | ||
| Protein | 101.0 g | 202% | |
| Vitamin D | 5.4 mcg | 27% | |
| Calcium | 2508 mg | 193% | |
| Iron | 7.9 mg | 44% | |
| Potassium | 1951 mg | 42% | |
*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.