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Zucchini and Squash Casserole Recipe

Zucchini and Squash Casserole

Wholesome Cove
This zucchini and squash casserole recipe layers tender summer vegetables with a creamy cheese sauce and a buttery cracker topping, then bakes until golden and bubbling. It's the perfect way to use up garden overflow and feeds a crowd with minimal effort.
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Prep Time 20 minutes
Cook Time 35 minutes
Total Time 55 minutes
Course Side Dish
Cuisine American
Servings 8 servings
Calories 285 kcal

Equipment

  • Sharp chef's knife
  • Mandoline slicer - optional
  • Large skillet
  • Colander
  • Mixing bowls - large one for cheese mixture, small one for topping
  • 9x13 inch baking dish - glass or ceramic
  • Box grater - if shredding your own cheese
  • Measuring cups and spoons
  • Rubber spatula
  • Aluminum foil - for tenting if needed
  • Salad spinner - optional but recommended

Ingredients
  

  • 2 pounds zucchini - 900g, sliced into ¼-inch rounds
  • 1.5 pounds yellow summer squash - 680g, sliced into ¼-inch rounds
  • 1 yellow onion - medium, diced
  • 3 tablespoons unsalted butter - 42g, for sautéing
  • 1 teaspoon kosher salt - plus more for sweating the squash
  • 0.5 teaspoon black pepper
  • 0.5 teaspoon garlic powder
  • 2 large eggs - beaten
  • 1 cup sour cream - 240g, full-fat recommended
  • 2 cups sharp cheddar cheese - 225g, shredded and divided (1½ cups for mixture, ½ cup for topping)
  • 0.5 cup Parmesan cheese - 50g, grated
  • 1 sleeve Ritz crackers - about 35 crackers, crushed
  • 0.25 cup butter - 60g, melted, for the topping
  • 2 tablespoons fresh parsley - chopped, for garnish (optional)

Instructions
 

  • Slice zucchini and yellow squash into even ¼-inch rounds. Spread on a baking sheet or in a colander, sprinkle generously with salt, and let sit for 15-20 minutes. Pat dry thoroughly with paper towels or a clean kitchen towel.
  • Preheat oven to 350°F (175°C) and grease a 9x13 baking dish. Melt 3 tablespoons butter in a large skillet over medium heat. Add diced onion and cook 4-5 minutes until translucent. Add squash slices and cook 4-6 minutes until crisp-tender. Season with salt, pepper, and garlic powder, then remove from heat.
  • In a large bowl, whisk eggs and sour cream until smooth. Fold in 1½ cups of the cheddar cheese and the Parmesan cheese. Gently fold in the sautéed vegetables until well coated.
  • Pour the squash mixture into the prepared baking dish and spread evenly. Sprinkle the reserved ½ cup of cheddar cheese over the top.
  • In a small bowl, combine crushed Ritz crackers with ¼ cup melted butter until all crumbs are coated. Sprinkle evenly over the cheese layer.
  • Bake uncovered for 30-35 minutes until golden brown and bubbling. Tent with foil if the top browns too quickly. Rest for 10 minutes before serving.

Notes

  • Don't skip salting: This step removes excess moisture and prevents a watery casserole. Squeeze or pat the squash very dry after salting.
  • Slice evenly: Use a mandoline for uniform ¼-inch slices so all pieces cook at the same rate.
  • Use full-fat sour cream: Light versions tend to separate and create a watery sauce when baked.
  • Shred your own cheese: Pre-shredded cheddar contains anti-caking starch that prevents smooth melting.
  • Make ahead: Assemble without the cracker topping up to 24 hours ahead, refrigerate, then add topping just before baking.
  • Gluten-free option: Substitute the Ritz crackers with gluten-free crackers or gluten-free panko breadcrumbs.
  • Variations: Try Mexican-style with pepper jack and green chiles, or Italian-style with mozzarella, basil, and panko.
  • Storage: Refrigerate leftovers in an airtight container for up to 4 days. Reheat covered at 350°F for 15-20 minutes.

Nutrition

Serving: 1servingCalories: 285kcalCarbohydrates: 13gProtein: 11gFat: 22gSaturated Fat: 12gPolyunsaturated Fat: 2gMonounsaturated Fat: 6gCholesterol: 90mgSodium: 410mgPotassium: 420mgFiber: 2gSugar: 5gVitamin A: 12IUVitamin C: 25mgCalcium: 20mgIron: 6mg
Keyword cheesy vegetable casserole, garden vegetable casserole, summer squash recipe, zucchini squash casserole
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