1-Begin with prepping and draining the squash. Wash and trim 2 pounds of yellow squash, then slice it into ¼-inch thick rounds. Place the slices in a colander, sprinkle with a bit of salt, and let them sit for 10 to 15 minutes to draw out excess moisture. Gently press or wrap in a clean kitchen towel to squeeze out the liquid, which helps prevent a watery casserole and ensures a firm bake.

2-Next, preheat your oven to 350 degrees Fahrenheit and grease a 1.5-quart baking dish. This step keeps everything ready for assembly. In a large pan, melt 1 tablespoon of butter over medium heat and add ½ cup diced onion. Sauté for 7 to 8 minutes until soft and translucent, then add the sliced squash and cook for 10 to 12 minutes, stirring frequently to release moisture without browning.

3-After cooking, drain the squash and onions in a colander lined with a towel for at least 5 minutes, pressing out excess moisture. In a bowl, mix the drained mixture with ½ teaspoon garlic powder, ¾ teaspoon salt, ½ teaspoon black pepper, ½ cup sour cream, 1 large beaten egg, 1 cup shredded cheddar cheese, and ¼ cup grated Parmesan cheese.

4-For the topping, melt the remaining 3 tablespoons of butter and stir it with 1 cup crushed butter crackers and the remaining ¼ cup grated Parmesan cheese. Transfer the squash mixture to your prepared baking dish and sprinkle the topping evenly over it.

5-Finally, bake at 350 degrees Fahrenheit for 25 minutes until golden brown. Let it rest for a few minutes before serving to allow the flavors to settle. This step-by-step approach makes your southern squash casserole turn out just right every time.