Southern Squash Casserole
Southern squash casserole should be creamy and set, with tender yellow squash slices that still hold their shape. Sautéing the squash with onion and red bell pepper, then draining it before adding the egg-and-cheddar filling, keeps excess liquid out of the baking dish.
Coarsely crushed buttery crackers form an uneven golden topping, with patches of melted cheddar between the pieces. Add the topping just before baking to keep it crisp, then finish with a light scattering of fresh thyme.
Ingredients for Southern Squash Casserole
- 3 pounds yellow summer squash, sliced 1/4 inch thick (1,350g)
- 1 medium yellow onion, finely diced (about 180g)
- 1 small red bell pepper, finely diced (about 120g)
- 6 tablespoons unsalted butter, divided (85g)
- 1 teaspoon kosher salt, plus more as needed
- 1/2 teaspoon black pepper
- 2 large eggs, lightly beaten
- 1/2 cup mayonnaise (120g)
- 1/2 cup sour cream (120g)
- 2 cups shredded sharp cheddar cheese, divided (225g)
- 1 tablespoon fresh thyme leaves, plus a few small sprigs for serving
- 2 cups coarsely crushed buttery round crackers (about 100g)
How to Make Southern Squash Casserole
- Prepare the dish: Heat the oven to 350°F (175°C). Lightly grease a shallow 2 1/2- to 3-quart casserole dish or a 9-by-13-inch baking dish with a little of the butter.
- Cook the vegetables: Melt 2 tablespoons of the butter, minus the amount used to grease the dish, in a large 12-inch skillet over medium heat. Add the squash, onion, red bell pepper, salt, and black pepper. Cook for 10 to 12 minutes, stirring gently now and then, until the squash is tender and pliable but the slices remain intact.
- Drain the squash: Transfer the vegetables to a colander and let drain for about 5 minutes. If they are still dripping heavily, press gently with the back of a spoon without mashing the squash.
- Mix the filling: In a large bowl, stir together the eggs, mayonnaise, sour cream, 1 1/2 cups of the cheddar, and most of the thyme leaves. Gently fold in the drained vegetables. The mixture should be thick and spoonable, not watery. Spread it in the prepared dish.
- Add the topping: Melt the remaining 4 tablespoons butter and toss with the crushed crackers. Scatter them loosely over the filling, leaving the pieces uneven rather than pressing them into a smooth layer. Sprinkle the remaining 1/2 cup cheddar in small patches so some crackers and squash remain visible.
- Bake: Bake uncovered for about 28 to 35 minutes, starting to check at 25 minutes. The edges should bubble, the cracker ridges should be golden, and the center should no longer look loose when the dish is gently nudged. If the topping browns before the center sets, tent the dish loosely with foil while it finishes baking.
- Rest and serve: Let the casserole rest for 5 to 10 minutes so the filling firms up for scooping. Scatter the remaining thyme leaves and a few small sprigs over the top. Serve warm.
How to Keep Squash Casserole From Getting Watery
Yellow squash releases plenty of moisture as it cooks. A wide skillet gives some of that liquid room to evaporate, but draining the cooked vegetables is still important. They should look moist without dripping heavily before you fold them into the filling; this recipe does not need added milk.
Stop sautéing when the squash is tender but still holds its shape. A shallow baking dish helps the center set evenly and leaves more surface area for the cracker topping. A deeper dish may need longer in the oven, so rely on the bubbling edges and set center rather than the timer alone.
Serving Ideas
Serve the casserole beside roast chicken, ham, or pork. For a simple dinner, add soft garlic butter dinner rolls. It also works alongside classic green bean casserole with crispy onions on a larger holiday table.
Make-Ahead, Storage, and Reheating
Make ahead: Assemble the filling in the baking dish, cover, and refrigerate for up to 24 hours. Keep the crackers and reserved cheddar separate. Toss the crackers with melted butter and add both toppings immediately before baking. A chilled casserole may need extra oven time for the center to set.
Store leftovers: Cool, cover tightly, and refrigerate for up to 4 days. The cracker topping will soften in the refrigerator. Add any extra fresh thyme after reheating.
Reheat: Warm leftovers in a 325°F (165°C) oven until hot. For a crisper top, add a small handful of fresh buttered cracker crumbs before reheating. Individual portions can be microwaved, though the crackers will remain softer.
Freeze: For convenience, freeze the unbaked filling without the cracker topping. Thaw overnight in the refrigerator, then add the topping and bake until the center sets. Freezing can soften the squash, so a freshly assembled casserole will have the best texture.
Nutrition
Approximate nutrition per serving, based on 8 side-dish servings: 440 calories, 13g protein, 37g fat, and 18g carbohydrates. Approximate values per 100g of finished casserole: 175 calories, 5g protein, 15g fat, and 7g carbohydrates. Values will vary with the crackers, mayonnaise, cheese, and amount of moisture drained from the squash.
Equipment
- 2 1/2- to 3-quart casserole dish
- 12-inch skillet
- colander
- large mixing bowl
- wooden spoon
Ingredients
For the Casserole
- 3 pounds yellow summer squash, sliced 1/4 inch thick (1,350g)
- 1 medium yellow onion, finely diced (about 180g)
- 1 small red bell pepper, finely diced (about 120g)
- 6 tablespoons unsalted butter, divided (85g)
- 1 teaspoon kosher salt, plus more as needed
- 1/2 teaspoon black pepper
- 2 large eggs, lightly beaten
- 1/2 cup mayonnaise (120g)
- 1/2 cup sour cream (120g)
- 1 1/2 cups shredded sharp cheddar cheese
For the Topping
- 2 cups coarsely crushed buttery round crackers (about 100g)
- 1/2 cup shredded sharp cheddar cheese
- 1 tablespoon fresh thyme leaves, divided
- A few small fresh thyme sprigs, for serving
Instructions
- Preheat the oven to 350°F (175°C). Lightly grease a shallow 2 1/2- to 3-quart casserole dish or a 9-by-13-inch baking dish with a little butter.
- Melt the remaining butter from the first 2 tablespoons in a large 12-inch skillet over medium heat.
- Add the squash, onion, red bell pepper, salt, and black pepper. Cook for 10 to 12 minutes, stirring gently occasionally, until the squash is tender and pliable but still holds its shape.
- Transfer the vegetables to a colander and drain for about 5 minutes. Press gently with the back of a spoon if they are still dripping heavily, without mashing the squash.
- Stir together the eggs, mayonnaise, sour cream, 1 1/2 cups cheddar, and most of the thyme leaves in a large bowl.
- Gently fold the drained vegetables into the egg mixture. Spread the filling evenly in the prepared baking dish.
- Melt the remaining 4 tablespoons butter and toss with the crushed crackers. Scatter the buttered crackers loosely over the filling.
- Sprinkle the remaining 1/2 cup cheddar over the top in small patches, leaving some crackers and squash visible.
- Bake uncovered for 28 to 35 minutes, checking at 25 minutes, until the edges are bubbling, the cracker topping is golden, and the center no longer looks loose when gently nudged.
- Tent loosely with foil if the topping browns before the center has set.
- Rest for 5 to 10 minutes before serving. Garnish with the remaining thyme leaves and fresh thyme sprigs.
Tips
- Use a wide skillet so moisture from the squash can evaporate as it cooks.
- Drain the cooked squash well before mixing it with the filling to prevent a watery casserole.
- Stop sautéing when the squash is tender but the slices still hold their shape.
- Add the cracker topping immediately before baking so it stays crisp.
- Use a shallow baking dish for more even setting and a crispier topping.
- Judge doneness by bubbling edges and a set center rather than the timer alone.
