This recipe for southern-style summer squash casserole is perfect for the abundance of zucchini and yellow squash you find at summer farmer's markets and in your own home garden. Summer squash and zucchini are some the easiest vegetables to grow if you want a crop that should be foolproof. Once your garden is going, you'll understand why you need recipes for what to do with all of the summer squash it produces. This casserole makes an excellent side dish or vegetarian main course. A casserole is always welcome at a potluck and it is easy for your guests to spoon out and serve themselves. Now that out-of-season produce is available year-round from some part of the world, this would make a terrific accompaniment for a holiday meal like thanksgiving, christmas, or even easter. It can also be adapted to use winter squash or to make in a slow cooker.