Zucchini and Squash Casserole
Tender rounds of zucchini and yellow squash are folded into a creamy, cheesy mixture and baked under a buttery cracker crumb topping until golden and bubbly. This classic Southern side dish comes together in under an hour with minimal prep and always disappears from the table first.
Equipment
- 9x13-inch baking dish heavy ceramic recommended for even heat distribution
- Large cast iron skillet or nonstick pan for sautéing
- Mandoline slicer optional, for even 1/4-inch slices
- Sharp knife if not using mandoline
- Box grater for shredding cheese from a block
- Colander for draining excess moisture from squash
- Mixing bowls
- Measuring cups and spoons
Ingredients
- 2 pounds zucchini and yellow squash about 900g total, sliced into 1/4 inch rounds
- 1 teaspoon salt for drawing out moisture
- 4 tablespoons unsalted butter 56g, divided (2 tbsp for sautéing, 2 tbsp for topping)
- 1 medium yellow onion about 1 cup or 150g, chopped
- 2 cloves garlic minced
- 1 cup sour cream 240g
- 2 large eggs beaten
- 2 cups sharp cheddar cheese 8 oz or 225g, shredded, divided (1 1/2 cups for filling, 1/2 cup for topping)
- 1/2 cup parmesan cheese 2 oz or 55g, grated
- 1/4 teaspoon black pepper
- 1/4 teaspoon paprika
- 1 1/2 cups Ritz crackers about 40 crackers, crushed
Instructions
- Preheat oven to 350°F and lightly grease a 9x13 inch baking dish. Slice squash into 1/4 inch thick rounds.
- Place sliced squash in a colander, sprinkle with 1 teaspoon salt, and toss. Let sit 10-15 minutes, then pat dry thoroughly with paper towels.
- Melt 2 tablespoons butter in a large skillet over medium heat. Add onion and cook 3-4 minutes until softened. Stir in garlic and cook 30 seconds until fragrant.
- Add dried squash to the skillet and cook 5-6 minutes until just barely tender. Remove from heat and cool slightly.
- In a large bowl, whisk together sour cream, beaten eggs, pepper, and paprika until smooth. Fold in 1 1/2 cups cheddar and the parmesan.
- Add the cooled squash mixture to the bowl and gently fold until evenly coated in the creamy mixture.
- Pour into the prepared baking dish and spread evenly. Sprinkle remaining 1/2 cup cheddar over the top.
- Toss crushed Ritz crackers with remaining 2 tablespoons melted butter. Scatter buttered crumbs evenly over the cheese layer.
- Bake uncovered 30-35 minutes until center is set and topping is golden brown. Tent with foil if topping browns too quickly.
- Let rest 10 minutes before serving to allow the casserole to set up. Serve warm.
Notes
- Do not skip salting and drying the squash — this step prevents excess water from making the casserole watery.
- Slice the squash evenly so every piece cooks at the same rate. A mandoline makes this quick and consistent.
- Use freshly shredded cheese rather than pre-shredded bags for a smoother melt and better flavor.
- Do not overcook the squash in the skillet — it will continue cooking in the oven and can become mushy.
- Let the casserole rest before serving so it firms up and slices cleanly.
- Swap the cheddar for pepper jack cheese for a little heat, or stir in cooked bacon for a smoky version.
- Refrigerate leftovers in an airtight container for up to 4 days. Reheat individual portions in the microwave or the full dish covered at 350°F for about 15 minutes.
- Freezing is not recommended, as the texture of the squash becomes watery after thawing.
- You can assemble the casserole up to a day ahead, cover, and refrigerate before baking.
- For a gluten-free version, substitute gluten-free crackers or gluten-free panko breadcrumbs.
Nutrition
Serving: 1servingCalories: 295kcalCarbohydrates: 13gProtein: 11gFat: 23gSaturated Fat: 13gPolyunsaturated Fat: 2gMonounsaturated Fat: 6gCholesterol: 95mgSodium: 480mgPotassium: 410mgFiber: 2gSugar: 5gVitamin A: 12IUVitamin C: 25mgCalcium: 20mgIron: 6mg
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