Creamy, cheesy, and kissed with buttery caramelized sweetness, this Vidalia Onion Casserole is comfort food at its finest. Rich Southern flavor meets irresistible texture in every spoonful.
Sweet onions steal the spotlight in this retro-style side dish, layered with melty cheese and finished with a buttery Ritz cracker crunch. It’s the kind of cozy indulgence you didn’t know you needed.
Star Players in This Vidalia Onion Casserole
- Vidalia onions – The soul of the dish; their natural sweetness deepens as they caramelize low and slow.
- Butter – Enhances the caramelization, giving the onions a silky richness.
- Sour cream – Adds tang and creaminess, balancing the sweetness of the onions.
- Mayonnaise – Lends a luscious, velvety mouthfeel and ties the filling together.
- Cheddar cheese – Sharp and melty, it brings body and boldness to the casserole.
- Parmesan cheese – Offers a nutty, salty depth that plays beautifully against the onions.
- Ritz crackers – Buttery and crisp, they deliver that craveable golden topping every casserole needs.
Let’s Cook Something Delicious: How to Make Vidalia Onion Casserole
Start by slowly caramelizing thinly sliced Vidalia onions in butter until golden, tender, and jammy. This takes time—around 45 to 60 minutes—but the flavor payoff is everything.
Once the onions are sweet and soft, mix them with sour cream, mayo, parmesan, and cheddar. Taste this moment; it’s already heavenly. Scrape it into a baking dish, top generously with crushed Ritz crackers, and bake until bubbly and golden on top.
This dish transforms humble ingredients into a decadent Southern side that feels both nostalgic and luxuriously comforting.
Southern Secrets & Simple Switch-Ups
For the best texture and flavor, use full-fat versions of the dairy and cheese. Pre-shredded cheese may save time, but shredding it yourself ensures a smoother melt and richer flavor.
Want to add a twist? Stir in crumbled bacon, a pinch of thyme, or a dash of hot sauce for a little extra flair. If you’re short on time, caramelize the onions the day before and store them chilled until you’re ready to assemble the dish.
Keep the Flavor Going: Storing Your Casserole
This casserole stores beautifully. If you’re prepping ahead, assemble everything and refrigerate it unbaked for up to four days. When ready to serve, bake uncovered until it’s bubbling and golden—just allow a few extra minutes if it’s going in straight from the fridge.
Leftovers can be stored in an airtight container in the fridge for up to three days. To reheat, cover with foil and warm in a 350°F oven until heated through, or zap single servings in the microwave. Avoid freezing, as the creamy texture may suffer.
Vidalia Onion Casserole
Ingredients
- ¼ cup sour cream
- 2 pounds sweet onions thinly sliced
- ½ stick butter
- ¼ cup grated Parmesan cheese
- 1 teaspoon kosher salt
- 2 ounces grated cheddar cheese approximately 1 cup
- ¼ cup mayonnaise
- Black pepper to taste
- 15 Ritz crackers or similar, crushed
Instructions
- Set a large nonstick skillet over low heat and introduce the butter, sliced onions, salt, and a generous amount of freshly ground black pepper. Allow the mixture to cook gently for 45 to 60 minutes, stirring occasionally. Ensure the onions remain just below browning, releasing their moisture and gradually turning tender and translucent with a light golden hue.
- Once the onions have fully softened and reduced, remove them from the heat and transfer them into a large mixing bowl. Prepare a 3 to 4-quart baking dish by coating it lightly with cooking spray.
- In the mixing bowl, combine the caramelized onions with mayonnaise, sour cream, Parmesan, and cheddar cheese. Mix until thoroughly blended, then taste and season with additional salt or pepper as needed.
- Evenly distribute the onion mixture into the prepared baking dish. Sprinkle the crushed crackers uniformly over the top to create a crisp topping.
- Place the dish in an oven preheated to 375°F and bake for 30 minutes or until the top is golden and the casserole is bubbling.
Notes
Dairy Quality: Full-fat sour cream, mayonnaise, and cheese are preferred for optimal flavor and consistency.
Dish Size: An 8×8-inch baking dish is ideal, though any medium-sized oven-safe dish will suffice.
Make Ahead: Assemble the casserole in advance and refrigerate covered for up to 4 days. When ready to serve, bake uncovered until thoroughly heated and bubbly, adding extra bake time if chilled.
