1. Preheat oven to 350°F (175°C) and grease a 9×13-inch baking dish.

2. In a large bowl, combine sliced squash, zucchini, and corn kernels.

3. In a separate bowl, whisk together milk, beaten eggs, sour cream, garlic powder, onion powder, paprika, salt, and pepper.

4. Add the milk mixture to the vegetables and stir until evenly coated.

5. Fold in cornmeal, crushed crackers, and half of the shredded cheddar cheese.

6. Pour the mixture into the prepared baking dish and smooth the top.

7. Sprinkle the remaining cheddar cheese over the casserole and drizzle with melted butter.

8. Bake for 40–45 minutes or until the center is set and the top is golden brown.

9. Remove from oven and let rest for 5–10 minutes before serving.