Onion Au Gratin
A rich and cheesy onion au gratin with caramelized onions and gooey cheddar, perfect as a comforting side or appetizer for family gatherings and casual dinners.
Ingredients
Instructions
- Mix cooked onions, 4 cups grated cheddar cheese, self-rising flour, black pepper, salt, and butter until well combined.
- Pour the mixture into a 2-quart casserole dish.
- Sprinkle the remaining 1 cup grated cheese evenly on top.
- Bake at 350°F for 30 minutes until bubbly and golden brown.
Tips & Substitutions
For an extra layer of flavor, consider adding sautéed garlic or herbs like thyme or rosemary to the onion mixture. If you don't have self-rising flour, you can substitute with all-purpose flour and add a teaspoon of baking powder. You can also experiment with different cheeses, such as Gruyère or mozzarella, for a unique twist on this dish.
Serving Suggestions
This rich and cheesy Onion Au Gratin pairs beautifully with a simple green salad or roasted vegetables for a balanced meal. It also works well as a hearty side dish alongside grilled meats or a comforting main course. For a delightful dessert to follow, consider serving Luscious Lemon Or Chocolate Pie to complete the meal.
Storage & Reheating
Leftover Onion Au Gratin can be stored in an airtight container in the refrigerator for up to 3 days. To reheat, place it in a preheated oven at 350°F for about 15-20 minutes, or until heated through and the cheese is bubbly. You can also microwave individual portions, but the oven method helps maintain the texture.
Nutrition & Diet Analysis (per serving)
Each serving of Onion Au Gratin contains roughly 693 calories, with 34g protein, 75g carbohydrates, and 37g fat. It is an excellent source of dietary fiber (91% of the Daily Value), calcium (89% of the Daily Value), and protein (69% of the Daily Value). Note that it is relatively high in sodium, at 1255mg per serving (55% of the Daily Value).
Estimated from ingredients & per-serving nutrition — verify against package labels for allergies or strict diets.
* % Daily Values based on a 2,000 calorie diet (FDA 2020).
Frequently Asked Questions
Can I use frozen onions for this recipe?
Yes, you can use frozen onions, but be sure to thaw and drain them thoroughly before using. This will prevent excess moisture in your dish, helping it bake evenly and achieve that desired golden brown finish.
Is it possible to make this dish ahead of time?
Absolutely! You can prepare the Onion Au Gratin up to a day in advance. Simply assemble the dish, cover it tightly, and refrigerate. When ready to serve, bake it directly from the fridge, adding a few extra minutes to the cooking time.
Can I make this recipe gluten-free?
Yes, you can make this dish gluten-free by using a gluten-free all-purpose flour blend instead of self-rising flour. Just add the appropriate amount of baking powder to mimic the leavening effect of self-rising flour.
Nutrition is estimated from USDA FoodData Central ingredient data and may vary with brand, portion and preparation — see our methodology. This information is for general educational purposes only and is not medical or dietary advice (disclaimer).