Old-School Squash Casserole

Get ready to fall head over heels for the ultimate comfort food that turns humble yellow squash into pure golden magic!

This isn’t just any casserole – it’s the kind of dish that makes people lean back in their chairs with satisfied sighs and immediately ask for the recipe.

We’re talking about layers of tender, buttery squash mingling with sharp cheddar and Swiss cheese, all crowned with a gloriously crunchy cracker topping that’ll have you fighting for the corner pieces.

The secret?

That perfect balance of creamy, cheesy goodness with just enough thyme to make your taste buds do a happy dance.

Ingredients

Active Time: 25 mins

Total Time: 1 hr 5 mins

Servings: 8

• 6 Tbsp. unsalted butter, divided
• 3 lbs. yellow squash, sliced 1/4-inch thick (from 5 medium squash)
• 1 medium-size yellow onion, chopped (about 1 1/2 cups)
• 2 tsp. kosher salt, divided
• 2 large eggs, lightly beaten
• 1 (8-oz.) container sour cream
• 4 oz. sharp Cheddar cheese, shredded (about 1 cup)
• 2 oz. Swiss cheese, shredded (about 1/2 cup)
• 1/2 cup mayonnaise
• 2 tsp. chopped fresh thyme
• 1/2 tsp. black pepper
• 2 sleeves round buttery crackers (such as Ritz), coarsely crushed
• 1 oz. Parmesan cheese, shredded (about 1/4 cup)

Steps

1. Prepare oven and baking dish: Preheat oven to 350°F (175°C). Grease an 11- x 7-inch (2 quart) baking dish with cooking spray. Make sure to coat the corners well – this prevents sticking and makes serving so much easier later.
2. Cook squash: Melt 3 tablespoons of the butter in a large skillet over medium-high heat. Add squash, onion, and 1 teaspoon of the salt; cook, stirring often, until center of squash is just tender and liquid has evaporated, about 10 minutes. You’ll know it’s ready when you can easily pierce the squash with a fork but it still holds its shape – mushy squash leads to watery casserole.
3. Drain liquid: Transfer mixture to a colander set over a bowl. Drain 5 minutes; discard any liquid. This step is crucial! Skipping the draining will result in a soggy casserole that never sets properly. Press gently with a spoon to encourage excess moisture to drain out.
4. Stir together casserole filling: Stir together eggs, sour cream, Cheddar and Swiss cheeses, mayonnaise, thyme, pepper, and remaining 1 teaspoon salt in a large bowl. Gently fold in squash mixture using a rubber spatula – aggressive stirring will break down the squash too much and create a mushy texture.
5. Spoon casserole filling into baking dish: Spoon mixture into the prepared 11- x 7-inch (2-quart) baking dish, spreading evenly with the back of a spoon. Level the surface for even cooking – any high spots might brown too quickly.
6. Make cracker topping: Microwave remaining 3 tablespoons butter in a medium-size microwavable bowl on HIGH until melted, about 25 seconds. Toss together crackers, Parmesan cheese, and melted butter until combined. The crackers should be coarsely crushed – not powder, but not whole either. Think pea-sized pieces for the perfect crunch.
7. Sprinkle topping over casserole: Distribute the cracker mixture evenly over the surface, making sure to reach all the edges. This creates that irresistible golden crust that makes this casserole so special.
8. Bake and serve: Bake in preheated oven until golden brown and bubbling around the edges, about 20 minutes. The topping should be deeply golden and the filling should be set when you gently shake the dish. Let cool for 5 minutes before serving – this helps it hold together when you scoop it out.

Smart Swaps

• Greek yogurt instead of sour cream (1:1 ratio) – adds protein without changing texture
• Panko breadcrumbs mixed with crushed crackers for extra crunch
• Fresh herbs like sage or rosemary instead of thyme for different flavor profiles

Make It Diabetes-Friendly

Replace the crackers with 1 cup crushed pork rinds mixed with 2 tablespoons almond flour to cut carbs by approximately 15g per serving. Swap the mayonnaise for 1/2 cup plain Greek yogurt, reducing carbs by another 2g per serving. Use full-fat sour cream and cheeses to help slow glucose absorption. This brings the total carbs down from about 18g to 8g per serving. Pair with a side salad with olive oil dressing to further minimize blood sugar spikes, and consider eating smaller portions (1/2 cup instead of 3/4 cup) to keep carbs under 6g per serving.

Pro Tips

• Salt the sliced squash and let it sit for 30 minutes before cooking to draw out even more moisture
• Shred your own cheese – pre-shredded has anti-caking agents that affect melting
• Toast the crushed crackers in a dry skillet for 2-3 minutes before mixing with butter for extra crunch