Cheesy Sweet Onion Casserole with Buttery Cracker Topping

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Baked cheesy onion casserole in a glass 13x9 dish with crisp buttery cracker topping and fresh parsley garnish.

Cheesy Sweet Onion Casserole with Buttery Cracker Topping

Creamy, cheesy, and full of tender, sweet onions, this comforting Onion Casserole is topped with buttery, golden crackers for the perfect balance of rich and crispy. It’s a cozy holiday side that’s easy enough for a weeknight dinner.

Course Side Dish

Cuisine American

Keyword casserole

Prep Time 15

Cook Time 47

Cooling Time 5

Total Time 1 7

Servings people

Calories 359kcal

Author Jillian Wade

Cost $10.95

Equipment

13x9-inch baking dish
large skillet
large mixing bowl
small mixing bowl
measuring cups and spoons
whisk
Spatula or spoon
Wire rack for cooling (optional)
Oven mitts

Ingredients

Casserole

5 large sweet onions about 12 cups, sliced ¼ inch thick (Use Vidalia, Walla Walla, or other sweet onions for best flavor.)
4 tablespoons unsalted butter
3 large eggs
1 ½ cups half-and-half
1 teaspoon salt
½ teaspoon black pepper
1 cup crushed buttery crackers like Ritz® or a similar round cracker
1 ½ cups shredded mild cheddar cheese or your favorite melting cheese

Topping

1 cup crushed buttery crackers
3 tablespoons unsalted butter melted

US Customary - Metric

Instructions

Prep the oven and pan

Preheat the oven to 350°F. Grease a 13×9-inch baking dish with butter or nonstick spray.

Cook the onions

In a large, heavy skillet, melt 4 tablespoons of butter over medium-low heat. Add the sliced onions and cook, stirring occasionally, until very soft and translucent, about 10–12 minutes. The onions should be tender but not browned.

Make the filling

Transfer the cooked onions to a large mixing bowl and let them cool for about 5 minutes.
In a separate small bowl, whisk together the eggs, half-and-half, salt, and pepper until smooth and well combined.
Pour the egg mixture over the slightly cooled onions. Add 1 cup crushed crackers and 1 ½ cups shredded cheddar, then stir gently until everything is evenly incorporated.

Assemble the casserole

Spread the onion mixture evenly into the prepared baking dish.

Make the topping

In a small bowl, combine 1 cup crushed crackers with 3 tablespoons melted butter. Stir until the crumbs are evenly coated. Sprinkle the topping evenly over the casserole.

Bake

Bake uncovered for 30–35 minutes, or until the topping is golden brown and the casserole is bubbly around the edges. The center should be just set, not jiggly, for the best texture (internal temperature should reach about 165°F).

Serve

Let the casserole rest on a wire rack for 5 minutes before serving. Enjoy warm!

Notes

Storage & Reheating

Refrigerate: Store leftovers in an airtight container for up to 3 days.
Reheat: Warm in a 350°F oven until heated through, or microwave individual portions.
Make ahead: Assemble the casserole (without baking) up to 24 hours in advance. Cover and refrigerate, then bake just before serving.

Nutrition