Southern Squash Casserole with Buttery Ritz Cracker Topping

Name: Southern Squash Casserole with Buttery Ritz Cracker Topping
Prep time: 25 min
Cook time: 50 min
Total time: 1 h 15 min
Yield: 8 servings
Cuisine: Southern
Ingredients: 2½ lb (1130 g) yellow summer squash, ends trimmed, sliced into ¼-inch (6 mm) rounds (about 8 medium squash... see note: use 6 to 7 medium); 1 tsp (5 g) kosher salt, for tossing with the squash (Diamond Crystal; use ¾ tsp if using Morton); 2 tbsp (28 g) unsalted butter; 1 large (about 12 oz) (340 g) sweet onion, halved and thinly sliced, then roughly chopped into ½-inch pieces; 2 cloves (8 g) garlic, minced; 8 oz (225 g) sharp cheddar cheese, freshly shredded from a block (about 2 cups), divided: 1½ cups for the filling, ½ cup for the top; 1 cup (230 g) full-fat sour cream, at room temperature; 1 large (50 g) large egg, at room temperature, lightly beaten; ½ tsp (1 g) black pepper, freshly ground; 1 tsp (5 ml) hot sauce, such as Tabasco or Crystal (optional); 32 crackers (about 1 sleeve plus a few) (100 g) Ritz crackers, coarsely crushed into pea-size crumbs (about 1½ cups); 4 tbsp (57 g) unsalted butter, melted; 1 tsp (5 g) unsalted butter, softened, for greasing the dish

From the MyKitchenBank Kitchen

Tender yellow squash and sweet onion are folded into a creamy sharp cheddar and sour cream sauce, then crowned with a golden, buttery Ritz cracker crust. Salting and draining the squash first keeps the casserole creamy, never watery.

Prep: 25 min
Cook: 50 min
Wait: 40 min
Total: 1 hr 55 min
Makes: 1 casserole (8 side-dish servings)

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Ingredients

8 servings

For the filling
2½ lb (1130 g) yellow summer squash, ends trimmed, sliced into ¼-inch (6 mm) rounds (about 8 medium squash... see note: use 6 to 7 medium)
1 tsp (5 g) kosher salt, for tossing with the squash (Diamond Crystal; use ¾ tsp if using Morton)
2 tbsp (28 g) unsalted butter
1 large (about 12 oz) (340 g) sweet onion, halved and thinly sliced, then roughly chopped into ½-inch pieces
2 cloves (8 g) garlic, minced
8 oz (225 g) sharp cheddar cheese, freshly shredded from a block (about 2 cups), divided: 1½ cups for the filling, ½ cup for the top
1 cup (230 g) full-fat sour cream, at room temperature
1 large (50 g) large egg, at room temperature, lightly beaten
½ tsp (1 g) black pepper, freshly ground
1 tsp (5 ml) hot sauce, such as Tabasco or Crystal (optional)
For the topping
32 crackers (about 1 sleeve plus a few) (100 g) Ritz crackers, coarsely crushed into pea-size crumbs (about 1½ cups)
4 tbsp (57 g) unsalted butter, melted
1 tsp (5 g) unsalted butter, softened, for greasing the dish

Equipment (8)

9×13-inch (23×33 cm) baking dish or 3-quart casserole
Large colander
Large skillet (12-inch / 30 cm)
Large mixing bowl
Clean kitchen towels or paper towels
Box grater
Small saucepan or microwave-safe bowl
Zip-top bag and rolling pin (or food processor)

Steps

Before you start

Plan for about 2 hours total: 30 minutes of the time is the squash draining and 10 minutes is the casserole resting at the end.
Shred the cheddar from a block yourself; pre-shredded cheese has anti-caking starch that makes the sauce grainy.
Let the egg and sour cream sit out for 20 minutes so they blend smoothly and don't cool the hot squash too much.
Do not preheat the oven until the squash is draining (step 3).

1
Salt the squash
- Trim the ends off the squash and slice into ¼-inch (6 mm) rounds.
- Place in a large colander set in the sink or over a bowl, toss with 1 teaspoon kosher salt, and spread out.
- Let drain for 30 minutes.
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Ready when: A visible puddle of liquid has collected under the colander and the slices look slightly glossy and limp
Tip: Skipping this step is the main cause of watery squash casserole.
2
Prep other ingredients
- While the squash drains, chop the onion, mince the garlic, and shred the cheddar into two piles: 1½ cups for the filling and ½ cup for the top.
- Let the sour cream and egg warm up on the counter.
3
Preheat and greaseOven 350°F / 175°C
- Set a rack in the center of the oven and heat to 350°F (175°C).
- Grease a 9×13-inch (23×33 cm) baking dish with the softened butter.
4
Press out the squash
- Spread the squash on a clean kitchen towel or a thick layer of paper towels.
- Fold over and press firmly to blot away as much moisture as you can.
- Do not rinse first.
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Ready when: The towel is damp and the slices feel only slightly moist, not wet
Tip: The squash is already seasoned from salting, so you will not need more salt later.
5
Sauté onion and squash
- Melt 2 tablespoons butter in a 12-inch (30 cm) skillet over medium heat.
- Add the onion and cook, stirring often, for 5 minutes until soft and translucent.
- Add the garlic and stir for 30 seconds until fragrant.
- Add the squash and cook, stirring occasionally, for 8 to 10 minutes.
- Leave the skillet uncovered so steam can escape.
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Ready when: Squash is tender when pierced with a fork, the slices are translucent at the edges, and little liquid remains in the pan
Tip: If the pan looks wet, raise the heat to medium-high for the last 2 minutes to cook off the liquid.
6
Cool the vegetables
- Transfer the squash mixture to a large mixing bowl and let it cool for 10 minutes.
- Drain off any liquid that pools at the bottom of the bowl.
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Ready when: The mixture is warm, not steaming hot
7
Make the creamy filling
- To the bowl, add 1½ cups of the cheddar, the sour cream, beaten egg, black pepper, and hot sauce if using.
- Fold gently with a spatula until evenly combined and creamy.
- Scrape into the prepared baking dish and spread into an even layer.
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Ready when: No streaks of sour cream remain and the squash is evenly coated
Tip: Fold gently so the squash slices don't break down into mush.
8
Make the topping
- Place the Ritz crackers in a zip-top bag and crush with a rolling pin into pea-size crumbs (or pulse a few times in a food processor).
- Pour into a bowl, add the melted butter, and toss with a fork until all crumbs look evenly moist.
- Stir in the remaining ½ cup cheddar if you like, or sprinkle it on first.
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Ready when: Crumbs clump slightly when pinched
Tip: Leave some larger pieces for crunch; don't grind into powder.
9
Top and bakeOven 350°F / 175°C
- Sprinkle the remaining ½ cup cheddar over the filling, then scatter the buttered cracker crumbs evenly on top.
- Bake at 350°F (175°C) on the center rack for 30 to 35 minutes.
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Ready when: Topping is deep golden brown and the edges are bubbling around the sides of the dish
Tip: If the topping browns too fast before the edges bubble, tent loosely with foil.
10
Rest and serve
- Remove from the oven and let the casserole rest on a wire rack for 10 minutes so the sauce thickens and can be scooped cleanly.
- Serve warm.
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Ready when: Bubbling has stopped and the filling looks set around the edges

Good to know

Tips

Slice the squash to an even ¼ inch so every piece cooks at the same rate.
Salting, draining, and pressing the squash is the key to a creamy, not watery, result. Don't skip it.
Use a sweet onion if you can find one; it melts into the sauce and adds gentle sweetness.
For extra crunch, toast the buttered crumbs in a dry skillet for 2 minutes before topping.

Make ahead

"Assemble the filling in the dish (through step 7), cover, and refrigerate up to 24 hours. Keep the buttered cracker topping separate in an airtight container at room temperature. Add the cheese and topping just before baking and add 5 to 10 minutes to the bake time, since the dish starts cold."

Storage & reheating

"Room temperature: up to 2 hours. Refrigerator: covered, up to 4 days. Freezer: not recommended, as the sour cream sauce can separate and the topping turns soggy. Reheat portions in a 350°F (175°C) oven for 15 to 20 minutes, uncovered, until hot in the center; the microwave works but softens the topping."

Substitutions

yellow summer squash → zucchini. Use the same weight. Zucchini holds a little more water, so press it well.
Ritz crackers → buttery round crackers or panko. If using panko, use 1 cup (50 g) and increase melted butter to 5 tablespoons, plus a pinch of salt.
full-fat sour cream → plain full-fat Greek yogurt or mayonnaise. Same amount. Yogurt adds more tang; mayonnaise gives a richer, more traditional Southern flavor.
sharp cheddar cheese → Colby Jack or Gruyère. Use the same amount, shredded from a block. Gruyère gives a nuttier flavor.