If you're a fan of nostalgic, easy, and budget-friendly side dishes, you'll adore Southern Sweet Onion Casserole. With melty cheese, buttery crackers, and loads of juicy onions, this cozy casserole is the perfect cold-weather remedy. Plus, you can assemble it ahead to give yourself a break during the busy holiday season!
Table of Contents
- 🗝️ Key takeaways: why this recipe is your new favorite
- 🧾 Gather your ingredients: what you'll need
- 📖 Make it your own: yummy variations
- 🔪 Step-by-step guide: instructions for success
- 🥫 Leftover love: how to store and reheat onion casserole
- Marye's Tip o' the day
- 💭 Insider tips: things to know
- 👩🍳 Let's answer those questions: FAQs
- 📚 More Southern comfort: related recipes you'll love
- 🍽️ No waste: creative ways to repurpose sweet onion casserole
- 📞 Wrapping it up: the last word
- 📖 Recipe
- 💬 Comments
Save this recipe by clicking on the ❤️ heart on the right-hand side of the screen or in the recipe card.
🗝️ Key takeaways: why this recipe is your new favorite
- Gooey and crisp, cheesy and buttery—this easy side dish has all the flavor and textures you crave!
- Southern sweet onion casserole is perfect for everything, from weeknight meals to Thanksgiving dinner and Christmas potlucks.
- Shredding the cheese fresh from a block is key to the creamiest casserole and best flavor.
Sweet onion casserole is a simple Southern staple that delivers big-time satisfaction. With just a couple of ingredients and less than ten minutes of prep time, you can have the best holiday side dish on the block!
🧾 Gather your ingredients: what you'll need
This is an overview of the ingredients. You'll find the full measurements and instructions in the green recipe card (printable) at the bottom of the page.
📖 Make it your own: yummy variations
- I like the buttery simplicity of Ritz crackers, but you could experiment with Cheez-Its or herbed breadcrumbs.
- Add freshly minced garlic for more savory flavor.
- Switch up the cheeses if you'd like—Smoked Gouda, Parmesan, Pepper Jack, or Swiss all add a nice flavor.
- Some people like to add a bit of a kick with smoked paprika, cayenne pepper, and/or even green chiles if you're feeling fun! It's not necessary, but it is a tasty Tex-Mex twist.
🔪 Step-by-step guide: instructions for success
This is an overview of the instructions. Full instructions are in the green recipe card at the bottom of the page. Click on the image to see it full size.
Simmer the onions until softened.
Drain onions and stir in butter.
Combine eggs and evaporated milk.
Add onions, crackers, and the cheese.
Stir well to combine the onion mixture.
Mix topping ingredients in a small bowl.
Spoon onion mixture into dish and add topping.
Bake at 375 degrees F for 40-45 minutes.
🤫 Marye's secret for zhuzhing it up -
Use a pretty, oven-safe casserole dish because you'll want to serve this from the same one you bake it in! Then, add some chopped parsley or green onion on top for an extra finishing touch.
zhuzh: verb. To make something more interesting or attractive
🥫 Leftover love: how to store and reheat onion casserole
Southern sweet onion casserole is one of those delicious sides that disappears surprisingly quickly from the dinner table.
However, if you have extras, cover the baking dish with foil (or transfer leftovers to an airtight container) and refrigerate for up to four days. You can also freeze onion casserole for up to three months.
After storing, the Ritz cracker topping will be a little soggy. The best way to reheat Southern onion casserole is in the oven—it'll crisp up the topping again.
You can also use the microwave to reheat individual servings, but you'll want to add freshly crushed crackers afterward to revive the crunch.
Marye's Tip o' the day
Slice the onions to ¼-inch thickness. Any smaller, and they'll cook down too much—you don't want 'em to disappear!
💭 Insider tips: things to know
- Sweet onions sometimes go by other names, like Vidalia, Maui, or Walla Walla.
- To cut onions in nice circles, slice a thin sliver off one of the sides as a base. Set the onion on this base for stability, then start cutting through the onion from the stem end.
- Don't let the onions get too soft while simmering. Just cook them until you can easily pierce them with a fork, about 6-8 minutes.
- Freshly shredded cheese tastes better and melts much smoother than pre-shredded cheese from a bag. In a simple recipe like this one, using good ingredients makes all the difference.
- Casserole dishes stay hot for a while, so when serving this to my family, I like to lay some pot holders over the dish handles to prevent anyone from accidentally grabbing the handle and getting a burn.
👩🍳 Let's answer those questions: FAQs
Have other questions? Ask me in the comments!
Sure. Most Spanish onions are on the sweeter side, though they won't be quite as sweet as varieties like Vidalia or Walla Wallas.
I don't recommend it. The flavor and texture won't be right. Red onions are best fresh, like on salads, tacos, and sandwiches.
It's simple. Just swap the Ritz crackers for your favorite gluten-free butter cracker. They likely won't taste quite as crisp as regular crackers, but it'll do the trick.
Nope, evaporated milk is thicker and less liquidy than regular milk. If you are absolutely in a pinch and need a last-minute swap, you could try heavy cream or cream cheese, instead.
⏲️ Marye's time saving hacks -
Make onion casserole ahead of time! Prepare the recipe as written, but don't make or add the cracker topping. Cover the dish and refrigerate for up to three days. When you're ready to enjoy it, let the dish warm up at room temperature, add the topping, and bake.
📚 More Southern comfort: related recipes you'll love
🍽️ No waste: creative ways to repurpose sweet onion casserole
Southern sweet onion casserole is a great side dish, but you can easily transform leftovers into a brand-new appetizer or meal:
- Flavorful Brunch—Stir the extra onion casserole into your favorite breakfast quiche recipe for an extra layer of flavor and texture.
- Quick Dinner—Warm leftovers. Stir in cooked macaroni, a half-cup pasta water, and shredded chicken. Add cheese/seasoning to taste.
- Party Appetizer—Spoon onion casserole into frozen phyllo shells from the grocery store. Add your favorite jam for a sweet/savory combo.
- Game Day Treat—Stir leftovers into your favorite no-bake tailgate recipe, like BLT Dip or Rotel Sausage Dip.
📞 Wrapping it up: the last word
If you click on the number of servings in the recipe card you can adjust the measurements up or down for the exact number of servings you need.
If you love this recipe please comment below and give it 5 stars! ⭐️⭐️⭐️⭐️⭐️
📖 Recipe
Southern Onion Casserole
Print Pin Recipe Save Recipe Rate RecipeIngredients
- 4 large onions, sliced to ¼-inch thickness, about 1 ½ pounds of onions
- 2 tablespoons butter
- 3 eggs
- ⅔ cup evaporated milk, 5 ounces
- 1 cup Ritz cracker crumbs
- 1 ½ cups grated cheddar cheese, grate from a block
- ½ cup Mozzarella, grated from a block.
- 1 teaspoon salt
- ¼ teaspoon black pepper
Topping:
- 1 cup Ritz cracker crumbs, coarsely crushed
- 3 tablespoons butter, melted
Instructions
- Grease a 13x9 inch pan.
- Preheat the oven to 375F.
- Place onions in a saucepan and cover with water.
- Bring to a boil and simmer until tender - about 6-8 minutes.
- Drain and put back in the pan.
- Stir in butter.
- In a large mixing bowl whisk the eggs and evaporated milk together until combined. Add the onion and butter mixture.
- Stir in the Ritz cracker crumbs, grated cheddar cheese, grated Mozzarella, salt, and pepper.
- Add to prepared 13x9-inch pan.
- Combine topping ingredients in a small mixing bowl and sprinkle on top of the mixture in the prepared pan.
- Bake for 40-45 minutes, or until heated through. It will register 165F on an instant read thermometer.
Notes
- Sweet onions sometimes go by other names, like Vidalia, Maui, or Walla Walla.
- Cut ¼ inch thick for best results.
- Don't let the onions get too soft while simmering. Just cook them until you can easily pierce them with a fork, about 6-8 minutes.
- Freshly shredded cheese tastes better and melts much smoother than pre-shredded cheese from a bag.
Nutrition Facts
Nutrition information is estimated as a courtesy. If using for medical purposes, please verify information using your own nutritional calculator. Percent Daily Values are based on a 2000 calorie diet.
This recipe has been tested several times. If you choose to use other ingredients, or change the technique in some way, the results may not be the same.
Wanda Saathoff says
All your recipes has my mouth watering! I can't wait to get in the kitchen and try the majority of them...