About Brenda Gantt’s Onion Casserole
Brenda Gantt is a Southern home cook from Andalusia, Alabama, whose unhurried, no-fuss cooking videos have drawn millions of fans. Her style leans on pantry staples like butter, mayonnaise, canned soup, and Ritz crackers, and it turns humble vegetables into dishes that show up on the table at every family gathering. You can read more about her in our stories and catch the latest in our news section.
Onion casserole fits right into that tradition. Sweet onions, which are known for their mild flavor, are cooked slowly in butter until soft and golden, then baked in a creamy, cheesy sauce under a crisp, buttery topping. Even people who say they don’t love onions tend to go back for more, because the long cooking brings out the sweetness and leaves none of the sharp bite.
Baked cracker-topped vegetable casseroles have long been a Southern staple for holiday tables, church suppers, and potlucks. Onion casserole is rich enough to serve with a roast or a holiday ham, yet simple enough for a weeknight. It also works as a brunch side, so check our breakfast recipes for more ideas to serve alongside it.
Watch How It’s Made
Prefer YouTube? Watch the original video.
Brenda Gantt Onion Casserole Recipe
Ingredients
Casserole
Cracker Topping
Kitchen Tools Needed
- Large skillet
- Large mixing bowl
- 2-quart baking dish
- Sharp knife & cutting board
- Measuring cups & spoons
New to slicing onions or choosing a baking dish? See our kitchen guides.
Instructions
- Preheat and prep. Preheat the oven to 350°F (175°C). Grease a 2-quart (or 11×7 inch) baking dish.
- Cook the onions. Melt 4 tablespoons butter in a large skillet over medium heat. Add the sliced onions and cook, stirring often, for 15 to 20 minutes until soft, golden, and lightly caramelized. Stir in the salt and pepper.
- Mix the sauce. In a large bowl, stir together the cream of chicken soup, sour cream, milk, and soy sauce until smooth. Fold in the cooked onions, the Swiss cheese, and half of the cheddar.
- Assemble. Spoon the mixture into the prepared baking dish and spread evenly. Sprinkle the remaining cheddar over the top.
- Add the topping. In a small bowl, mix the crushed Ritz crackers with the ¼ cup melted butter. Sprinkle evenly over the casserole.
- Bake. Bake uncovered for 25 to 30 minutes, until bubbly around the edges and golden brown on top.
- Rest and serve. Let the casserole rest for 10 minutes so it sets, then serve warm.
Take your time with the onions. Cooking them slowly until golden is what gives this casserole its sweet, mellow flavor.
Nutrition Facts
| Calories | 390 |
|---|---|
| Protein | 10 g |
| Carbohydrates | 24 g |
| Fat | 27 g |
| Fiber | 2 g |
| Sodium | 700 mg |
| Sugar | 8 g |
Nutrition values are estimates and are not a substitute for professional dietary advice.
Health Benefits of Onion Casserole
Antioxidant Compounds
Onions contain flavonoids such as quercetin, plant compounds studied for their antioxidant properties.
Prebiotic Fiber
Onions contain prebiotic fibers that feed beneficial gut bacteria and support digestion.
Calcium Source
Swiss and cheddar cheese provide calcium and protein, which support bone health.
Satisfying Side
The fat and protein from the cheese and sour cream help you feel full, so a modest serving goes a long way.
What to Avoid
Preparation Mistakes
- Don’t rush the onions. Undercooked onions stay sharp and release water in the oven. Cook them until soft and golden.
- Don’t crush the crackers to dust. Keep them coarse for a better crunch.
- Don’t under-bake. Wait for a golden top and bubbling edges so the sauce fully sets.
Storage Mistakes
- Don’t store it while hot. Cool it fully first to prevent condensation and a soggy topping.
- Don’t freeze it with the topping on. The dairy sauce can separate, so refrigerate leftovers instead and add fresh crackers when reheating.
Dietary Considerations
- Contains Dairy (cheese, sour cream, butter, milk)
- Contains Gluten (crackers, soup)
- Contains Soy (soy sauce)
- Moderate Sodium
Pro Tips for the Best Onion Casserole
- Slice evenly. Thin, even slices cook at the same rate and melt into the sauce.
- Use sweet onions. Vidalia, Walla Walla, or Texas sweet onions give the mildest, sweetest result.
- Add the soy sauce. A small splash adds savory depth without making the dish taste of soy.
- Shred your own cheese. Freshly shredded cheese melts smoother than pre-shredded.
- Let it rest before serving. Ten minutes out of the oven helps the casserole set so it scoops cleanly.
Want more techniques like these? Browse our cooking tips.
What to Serve With Onion Casserole
Beverages
- Sweet tea
- Chardonnay
- Lemonade
Main Dishes
- Meatloaf
- Baked ham
- Roast chicken
- Pork tenderloin
Side Dishes
When to serve: Sunday supper, holiday dinners, potlucks, and cookouts. For a cool side to balance the richness, try our macaroni salad or Jell-O salad, and finish with key lime pie.
Ingredient Substitutions
| Ingredient | Swap | Notes |
|---|---|---|
| Sweet onions | Yellow onions | Sharper flavor; cook a few minutes longer. |
| Cream of chicken soup | Cream of mushroom or cream of celery soup | Each gives a slightly different flavor. |
| Sour cream | Plain Greek yogurt | Adds tang; use full-fat. |
| Swiss cheese | Gruyère, Monterey Jack, or more cheddar | Gruyère gives a nuttier flavor. |
| Ritz crackers | Club crackers, panko, or French fried onions | Toss with melted butter so it browns evenly. |
Storage & Reheating
Refrigerator
Cool completely, then store in an airtight container for 3 to 4 days.
Freezer
Not recommended, since the dairy sauce can separate when thawed. Refrigerate leftovers instead.
Reheating
Oven at 350°F for about 20 minutes, adding fresh buttered cracker crumbs on top. Microwave individual servings.
Make ahead: assemble the casserole without the topping, cover, and refrigerate up to 24 hours. Add the topping just before baking.
Frequently Asked Questions
Yes. Yellow onions work, but they are sharper and less sweet. Cook them a few minutes longer until they are soft and golden, and add a pinch of sugar if you want a milder flavor.
You don’t need a deep brown, but cooking the onions until they are soft and lightly golden is important. It removes their raw bite, brings out their sweetness, and cooks off extra moisture so the casserole doesn’t turn watery.
Yes. Assemble the casserole without the cracker topping, cover, and refrigerate for up to 24 hours. Add the buttered cracker topping just before baking so it stays crisp, and allow 5 to 10 extra minutes if the dish goes in cold.
Onions hold a lot of water. If they aren’t cooked down enough before baking, that liquid ends up in the sauce. Cook them until they are soft and the skillet is mostly dry, and bake until the center is bubbling, not just warm.
It’s not ideal. Dairy-based sauces can separate and turn grainy after freezing and thawing. Refrigerate leftovers for 3 to 4 days instead. If you do freeze it, freeze without the topping, thaw overnight in the fridge, and add fresh buttered crackers before reheating.
Club crackers, panko breadcrumbs, crushed cornflakes, or French fried onions all make a good crunchy topping. Toss whichever you choose with melted butter so it browns evenly.
Reader Reviews
More Brenda Gantt Recipes
- Mashed PotatoesA creamy classic that pairs with onion casserole
- MeatloafHearty Southern dinner to serve alongside
- Mac and CheeseAnother cheesy Southern comfort side
- Macaroni SaladA cool, creamy side for cookouts
- Jell-O SaladA nostalgic potluck favorite
- Mayonnaise RollsEasy rolls for sopping up every bite
- JambalayaA bold one-pot meal
- JackfruitA meatless twist on Southern cooking
- Key Lime PieA tangy, sweet finish to the meal
Explore the Site
It’s gonna be good, y’all. Make it for your next family supper.
Back to Recipe