1. Preheat your oven to 350°F (175°C). This is the perfect temperature for a bubbly, golden casserole.
2. In a large skillet over medium heat, melt a tablespoon of butter. Add the diced onions and sliced squash. Sauté for about 5-7 minutes until the squash is tender and the onions are translucent. You’ll want to stir occasionally, letting the flavors meld together.
3. In a mixing bowl, whisk together the eggs, milk, salt, pepper, and garlic powder. This mixture will bring everything together into a creamy delight.
4. In a large bowl, combine the sautéed squash and onions with the egg mixture, then fold in 1 1/2 cups of the shredded cheese and 1/2 cup of the crushed crackers. Stir gently until everything is well mixed.
5. Pour the mixture into a greased 9×13-inch baking dish. Top with the remaining cheese and crushed crackers, then drizzle the melted butter over the top for that golden crispiness.
6. Bake in the preheated oven for 30-35 minutes, or until the top is golden brown and the casserole is set. You’ll know it’s ready when the edges are bubbling and the center isn’t jiggly.
7. Let it cool for a few minutes before serving. This is a great time to set the table and gather your family—trust me, you’ll want to enjoy this fresh out of the oven!

From my experience, taking that extra moment to let it cool slightly helps the casserole set up and makes serving easier. Plus, it gives you just enough time to relish the aroma filling your kitchen.