Jump to Recipe Print RecipeAs I opened the fridge, the sweet aroma of Vidalia onions wafted right out, igniting the memories of family gatherings and rich Southern feasts. This Southern Sweet Onion Casserole is more than just a dish; it’s a comforting hug on a plate, perfect for cozy Sunday dinners or festive holidays. Made with creamy layers of sweet onions enveloped in a decadent cheese mixture and crowned with buttery breadcrumbs, it offers both a savory and slightly sweet symphony of flavors. Not only is it a budget-friendly option that feeds a crowd, but it can easily be adapted to accommodate gluten-free diets, making it a versatile addition to your meal rotation. Can you imagine serving this delightful casserole alongside your favorite roast? Let’s dive into how to whip up this nostalgic dish that’s destined to become a staple in your home! Why is This Casserole a Must-Try? Comforting warmth in every bite: This Southern Sweet Onion Casserole isn’t just food; it’s nostalgia on a plate, bringing families together for wholesome meals. Easily adaptable: Whether you want a gluten-free option or to jazz it up with bacon, this dish caters to your style. Quick prep: With simple steps, you can savor homemade goodness in no time. Crowd pleaser: Perfect for gatherings, it pairs beautifully with roasted meats, making it the star of any dinner table! Budget-friendly: Enjoy a rich, creamy delight without breaking the bank, ensuring everyone leaves satisfied. For a side that’s equally impressive, check out our Sweet Potato Rounds as a delicious companion! Southern Sweet Onion Casserole Ingredients For the Casserole Sweet Onions – The star ingredient providing rich sweetness; Vidalia onions are particularly recommended. Unsalted Butter – Adds richness and helps soften the onions during cooking. Salt – Enhances the natural flavors of this Southern Sweet Onion Casserole. Black Pepper – Offers a subtle heat that perfectly balances the sweetness. Sugar (Optional) – Adds an extra kick of sweetness; not necessary but recommended if you like it sweeter. Shredded Sharp Cheddar Cheese – Adds creaminess and a tangy flavor that pairs well with onions. Shredded Mozzarella Cheese – Introduces a stretchy texture and extra creaminess. Sour Cream – Contributes to the rich, creamy texture of the casserole. Large Eggs – Serve as a binder, ensuring your casserole holds together beautifully. Crushed Butter Crackers (like Ritz) – Creates that beloved crunchy topping. Melted Butter (for topping) – Boosts the crispiness of the cracker layer for that delightful contrast. Enjoy crafting this comforting dish that’s bound to become a family favorite! Step‑by‑Step Instructions for Southern Sweet Onion Casserole Step 1: Prepare the Onions Begin by slicing the sweet onions thinly, aiming for uniform pieces to ensure even cooking. In a large skillet, melt 2 tablespoons of unsalted butter over medium heat. Add the onions and sauté for about 15 minutes, stirring occasionally, until they are soft and lightly golden. This step enhances the sweetness of the onions, bringing out their natural flavors, which will be the heart of the Southern Sweet Onion Casserole. Step 2: Mix the Filling In a mixing bowl, combine the sautéed onions with 1 cup of sour cream, 2 beaten large eggs, 1 teaspoon of salt, ½ teaspoon of black pepper, and half of your shredded cheeses (1 cup of sharp cheddar and ½ cup of mozzarella). Mix until fully incorporated and smooth, ensuring everything is well blended. This creamy mixture will serve as the base of the casserole, providing rich flavor and texture. Step 3: Assemble the Casserole Grease a 9×13-inch baking dish with butter to prevent sticking. Pour the onion filling into the dish, spreading it evenly. Sprinkle the remaining cheeses on top, followed by a mixture of crushed butter crackers (about 1 cup) and 2 tablespoons of melted butter. This topping will add a delightful crunch as it bakes, making your Southern Sweet Onion Casserole even more inviting. Step 4: Bake Preheat your oven to 350°F (175°C) to ensure it’s ready for baking. Carefully place the assembled casserole in the oven and bake for 30-35 minutes. Watch for a golden brown top and bubbling around the edges as indicators that it’s done. The cheese should be perfectly melted and the cracker topping crisp, creating a harmonious contrast with the creamy filling. Step 5: Serve Once baked, remove the casserole from the oven and allow it to rest for about 5-10 minutes. This resting period helps the casserole set for easier serving and better texture. Slice and scoop generous portions to share with your loved ones. Your Southern Sweet Onion Casserole is now ready to delight everyone at the table! Expert Tips for Southern Sweet Onion Casserole Sweet Onion Choice: Use Vidalia or Bermuda onions for the best sweetness. They are key to achieving the flavor that defines this Southern Sweet Onion Casserole. Sautéing Technique: Take your time while sautéing onions; a gentle cook over medium heat will caramelize them beautifully, enhancing their sweetness, rather than burning them. Mixing Ingredients: Ensure that your eggs are well-beaten before adding them to the mixture. This prevents any curdling and ensures a smooth, cohesive texture in your casserole. Testing Doneness: Look for a golden brown top and bubbling edges. If it browns too quickly, cover it loosely with foil to prevent burning while the inside cooks through perfectly. Reheating Method: When reheating leftovers, avoid the microwave. Instead, warm them in the oven to keep that crunchy topping intact, preserving the delightful texture of your Southern Sweet Onion Casserole. Southern Sweet Onion Casserole Variations Customize your Southern Sweet Onion Casserole to suit your taste buds with these delightful options! Cheesy Boost: Add extra layers of mozzarella or Gruyère cheese for an indulgent, cheesy experience that oozes flavor. Bacon Twist: For a savory crunch, fold in crispy, crumbled bacon; it adds a smoky richness that elevates the dish. Vegetarian Delight: Mix in sautéed mushrooms or fresh spinach to bring added nutrition and color, making it even more vibrant and appealing. Gluten-Free: Use gluten-free crackers or breadcrumbs as a tasty alternative to keep this comfort food accessible for everyone. Herb Infusion: Add fresh herbs like thyme or rosemary to the onion mixture for a fragrant, herby touch that complements the sweetness beautifully. Creamy Spin: Replace sour cream with a mix of cream cheese and Greek yogurt for a tangy and creamy layer that’s sure to please. French Onion Style: Stir in caramelized onions and a splash of beef broth for a rich, deep flavor that recalls classic French onion soup. Spicy Kick: Craving some heat? Toss in some diced jalapeños or a dash of hot sauce to give your casserole a lively, spicy twist. No matter how you choose to adapt this dish, it’s sure to be a crowd favorite. For a delicious accompanying side, consider serving it with Blooming Onions Flavor for a fun twist, or pair the casserole with our Bbq Chicken Rice for a hearty meal that satisfies! Make Ahead Options These Southern Sweet Onion Casseroles are perfect for meal prep enthusiasts looking to save time! For ultimate convenience, you can prepare the casserole up to 24 hours in advance. Simply follow the assembly instructions, cover the dish tightly with plastic wrap, and refrigerate until you’re ready to bake. The key is to hold off on adding the crispy topping until just before baking to maintain its crunch. When you’re ready to serve, preheat your oven to 350°F (175°C), uncover the casserole, sprinkle with the crushed crackers, and bake for 30-35 minutes until golden and bubbly. With these make-ahead tips, you’ll enjoy a stress-free meal that’s just as delicious as when freshly made! Storage Tips for Southern Sweet Onion Casserole Fridge: Store leftovers in an airtight container for up to 4 days. This keeps the flavors fresh and prevents drying out. Freezer: You can freeze the casserole for up to 2 months! Make sure it cools completely before wrapping it tightly in plastic wrap and aluminum foil. Reheating: For best results, reheat the Southern Sweet Onion Casserole in the oven at 350°F (175°C) for 20-25 minutes until heated through and the topping is crispy again. Make-Ahead: You can assemble the casserole a day in advance, refrigerate, and bake just before serving for ultimate convenience! What to Serve with Southern Sweet Onion Casserole Experience the delightful blend of flavors and comfort that makes your meal complete with these perfect pairings! Savory Ham: The saltiness of baked ham pairs beautifully with the sweet creaminess of the casserole, creating a classic combo. Roast Turkey: Juicy turkey brings a tender, savory contrast to the casserole’s richness, making it a festive feast favorite. Barbecued Ribs: The smoky sweetness from barbecue glaze enhances the casserole, bringing in a delightful flavor explosion in every bite. Steamed Green Beans: Their crisp texture and freshness provide a refreshing counterpoint to the creamy layers of the casserole. Garlic Bread: Crispy garlic bread complements the soft, cheesy goodness of the casserole, perfect for scooping up every bite. Spinach Salad: A light salad with tangy vinaigrette adds a refreshing crunch that balances out the casserole’s richness. Fruity Sangria: The sweetness and fruity notes in sangria refresh the palate, enhancing the overall dining experience. Apple Crisp: For dessert, a warm apple crisp serves as a sweet finish, echoing the casserole’s comforting vibe in a whole new way! Southern Sweet Onion Casserole Recipe FAQs What type of sweet onions should I use for the casserole? Absolutely! Vidalia onions are highly recommended for their exceptional sweetness, but you can also use Bermuda or Walla Walla onions if Vidalia isn’t available. The key is to choose onions with a sweet flavor profile to achieve that rich, comforting taste in your Southern Sweet Onion Casserole. How should I store leftovers of the casserole? For optimal freshness, store any leftover Southern Sweet Onion Casserole in an airtight container in the refrigerator for up to 4 days. This keeps all the delicious flavors intact and prevents them from drying out. Can I freeze the Southern Sweet Onion Casserole? Yes, you can freeze the casserole for up to 2 months! Allow it to cool completely, then wrap it tightly with plastic wrap followed by aluminum foil to prevent freezer burn. When you’re ready to enjoy it again, simply thaw in the refrigerator overnight and reheat in the oven at 350°F (175°C) for about 20-25 minutes until heated through. What can I do if the casserole comes out too watery? If your Southern Sweet Onion Casserole ends up a bit too watery, it could be due to not cooking out enough moisture from the onions during the sautéing step. For next time, try sautéing the onions on medium heat a little longer until they are soft and lightly golden before mixing them into the casserole. You could also add an extra egg to help bind the mixture or consider reducing the sour cream slightly. Is this casserole suitable for gluten-free diets? Very much so! You can easily make this Southern Sweet Onion Casserole gluten-free by substituting the crushed butter crackers with gluten-free alternatives like crushed GF crackers or gluten-free breadcrumbs. Additionally, double-check your other ingredients, such as cheese and butter, to ensure they are gluten-free as well. What are the best ways to serve this casserole? I recommend serving your Southern Sweet Onion Casserole with roasted meats like ham, turkey, or brisket for a delightful, comforting meal. It also pairs beautifully with barbecue dishes or can be a star on your Thanksgiving table! Don’t forget to garnish with freshly chopped herbs for an extra touch of color and flavor. Southern Sweet Onion Casserole: Comforting and Cheesy Delight This Southern Sweet Onion Casserole is a comforting hug on a plate, featuring creamy layers of sweet onions and decadent cheese. Print Recipe Pin Recipe Prep Time 15 minutes minsCook Time 35 minutes minsResting Time 10 minutes minsTotal Time 1 hour hr Servings: 8 slicesCourse: DinnerCuisine: SouthernCalories: 350 Ingredients Equipment Method Nutrition Notes Ingredients 1x2x3x? For the Casserole4 cups Sweet Onions Vidalia onions recommended2 tablespoons Unsalted Butter For sautéing onions1 teaspoon Salt To enhance flavors1/2 teaspoon Black Pepper For balance1 tablespoon Sugar Optional for extra sweetness1 cup Shredded Sharp Cheddar Cheese1/2 cup Shredded Mozzarella Cheese1 cup Sour Cream2 Large Eggs Beaten1 cup Crushed Butter Crackers Like Ritz2 tablespoons Melted Butter For topping Equipment SkilletMixing bowl9x13-inch baking dish Method Step-by-Step InstructionsBegin by slicing the sweet onions thinly. In a skillet, melt 2 tablespoons of unsalted butter over medium heat. Add onions and sauté until soft and lightly golden.In a mixing bowl, combine the sautéed onions with sour cream, beaten eggs, salt, black pepper, and half of the shredded cheeses. Mix until smooth.Grease a 9x13-inch baking dish with butter. Pour the onion filling into the dish, spreading it evenly. Sprinkle remaining cheeses and crushed butter crackers on top, followed by melted butter.Preheat your oven to 350°F (175°C). Bake the casserole for 30-35 minutes until golden brown on top and bubbling around edges.Remove casserole from the oven and let it rest for 5-10 minutes before slicing and serving. Nutrition Serving: 1sliceCalories: 350kcalCarbohydrates: 30gProtein: 10gFat: 20gSaturated Fat: 10gPolyunsaturated Fat: 2gMonounsaturated Fat: 5gCholesterol: 80mgSodium: 600mgPotassium: 300mgFiber: 1gSugar: 4gVitamin A: 500IUVitamin C: 5mgCalcium: 200mgIron: 1mg NotesFor best flavor, use Vidalia or Bermuda onions. Sauté onions gently to caramelize without burning. This casserole can be prepared a day in advance and refrigerated before baking. Tried this recipe?Let us know how it was!