Southern squash casserole bakes tender yellow squash with a buttery cracker topping for a family-favorite vegetarian side. Creamy, comforting, and perfect alongside any protein for holiday meals and summer suppers.
Preheat oven to 350°F and lightly butter a 9x13-inch baking dish.
Slice yellow squash into 1/4-inch rounds; finely dice onion. Sauté squash and onion in 2 tbsp butter over medium heat for about 10 minutes, stirring frequently until fork-tender but not mushy.
Transfer cooked squash and onions to a colander and gently press out excess moisture to prevent a watery casserole.
In a large bowl, whisk eggs, sour cream, salt, pepper, and garlic powder; fold in shredded cheddar and half the crushed crackers.
Stir in the drained squash mixture, combine gently, then pour into the baking dish. Top with remaining crushed crackers and dot with the remaining 2 tbsp melted butter.
Bake uncovered for 35-40 minutes until the top is golden and the casserole is set but still creamy in the center. Rest for 10 minutes before serving to allow structure to finish setting.