Golden Southern Summer Squash Casserole

🌍 Cuisine: American Southern
🏷️ Category: Side Dish
⏱️ Prep: 20 minutes
🍳 Cook: 35-40 minutes
👥 Serves: 6-8 servings

📝 About This Recipe

This quintessential Southern comfort dish transforms humble summer squash into a decadent, velvety masterpiece that captures the essence of a backyard garden harvest. Slices of tender yellow squash are sautéed with sweet onions and folded into a rich, savory custard of sharp cheddar and herb-infused cream. Topped with a signature buttery cracker crust for that essential crunch, this casserole is the ultimate nostalgic side dish for Sunday dinners and holiday gatherings alike.

🥗 Ingredients

The Vegetable Base

  • 2.5 pounds Yellow Summer Squash (sliced into 1/4-inch thick rounds)
  • 1 large Sweet Vidalia Onion (finely diced)
  • 4 tablespoons Unsalted Butter (divided for sautéing)
  • 3 cloves Garlic (minced)
  • 1/4 cup Water (for steaming)

The Binding Sauce

  • 1/2 cup Sour Cream (full fat preferred)
  • 1/2 cup Mayonnaise (high quality, like Duke's)
  • 1 Large Egg (beaten)
  • 1.5 cups Sharp Cheddar Cheese (freshly shredded)
  • 1/4 cup Parmesan Cheese (finely grated)
  • 1 teaspoon Kosher Salt (plus more to taste)
  • 1/2 teaspoon Black Pepper (freshly cracked)
  • 1/2 teaspoon Dried Thyme

The Topping

  • 1 sleeve Ritz Crackers (about 30-35 crackers, crushed)
  • 3 tablespoons Unsalted Butter (melted)
  • 1/4 teaspoon Smoked Paprika (for color and depth)

👨‍🍳 Instructions

  1. 1

    Preheat your oven to 350°F (175°C) and lightly grease a 9x13 inch baking dish or a 2.5-quart casserole dish with butter or non-stick spray.

  2. 2

    In a large skillet or Dutch oven, melt 2 tablespoons of butter over medium-high heat. Add the diced onions and sauté for 3-4 minutes until they begin to soften and turn translucent.

  3. 3

    Add the sliced yellow squash to the skillet along with the 1/4 cup of water. Cover with a lid and steam for about 5-7 minutes, stirring occasionally, until the squash is fork-tender but not mushy.

  4. 4

    Uncover the skillet and add the remaining 2 tablespoons of butter and the minced garlic. Sauté for another 2 minutes to evaporate any excess liquid. This step is crucial to prevent a watery casserole.

  5. 5

    Transfer the squash and onion mixture to a colander and let it drain for 5 minutes. Press down very gently with a spoon to release any trapped moisture.

  6. 6

    In a large mixing bowl, whisk together the sour cream, mayonnaise, beaten egg, salt, pepper, and dried thyme until smooth.

  7. 7

    Fold in 1 cup of the shredded cheddar cheese and the grated Parmesan cheese into the creamy mixture.

  8. 8

    Add the drained squash and onions to the bowl and gently toss until every slice is thoroughly coated in the sauce.

  9. 9

    Pour the mixture into your prepared baking dish, spreading it out into an even layer. Sprinkle the remaining 1/2 cup of cheddar cheese over the top.

  10. 10

    In a small bowl, combine the crushed Ritz crackers, melted butter, and smoked paprika. Stir until the crumbs are evenly moistened.

  11. 11

    Scatter the cracker mixture evenly over the top of the casserole, ensuring full coverage for maximum crunch.

  12. 12

    Bake in the center rack of the oven for 30-35 minutes, or until the topping is a deep golden brown and the edges are bubbling vigorously.

  13. 13

    Remove from the oven and allow the casserole to rest for 5-10 minutes before serving. This allows the sauce to set so it isn't too runny when scooped.

💡 Chef's Tips

Always drain your squash thoroughly after sautéing; squash holds a lot of water which can thin out your sauce if not removed. For the best texture, grate your own cheese from a block; pre-shredded cheeses are coated in potato starch which prevents a smooth melt. If you want a bit of heat, add a pinch of cayenne pepper or a dash of hot sauce to the egg and cream mixture. You can substitute zucchini for half of the yellow squash for a beautiful color contrast. If the crackers are browning too quickly, tent the dish loosely with foil for the last 10 minutes of baking.

🍽️ Serving Suggestions

Serve alongside Southern fried chicken or honey-glazed ham for a traditional feast. Pairs beautifully with a crisp, chilled Chardonnay or a glass of sweetened iced tea. Add a side of buttery cornbread or buttermilk biscuits to soak up the extra sauce. Serve as a vegetarian main course over a bed of fluffy white rice or quinoa.