1. Preheat oven to 375°F (190°C) and grease a 9×13-inch casserole dish

2. Wash and slice yellow squash and zucchini into thin rounds

3. Shuck corn if using fresh and slice kernels off the cob or thaw and drain frozen corn

4. In a large skillet over medium heat melt butter or heat oil

5. Sauté chopped onion and garlic until fragrant, about 3 minutes

6. Add squash slices and cook 3–4 minutes until slightly tender

7. Stir in corn kernels, salt, pepper, paprika, and parsley, then remove from heat

8. In a bowl whisk together heavy cream or milk and shredded cheese

9. Layer a thin layer of the cream mixture in the casserole dish, then add half of the squash and corn mixture

10. Repeat layers and pour remaining cream mixture on top

11. Sprinkle breadcrumbs or crushed crackers over casserole

12. Cover dish with foil and bake 25 minutes

13. Remove foil and bake an additional 20 minutes until top is golden and bubbly

14. Let casserole rest 5–10 minutes before serving