Summer Squash Casserole is a rich flavorful side dish that you can serve year round. This creamy recipe starts on the stove top and finishes in the oven.
Preheat oven to 400 degrees F.
Melt butter over medium high heat in large oven safe skillet. Place squash, zucchini, and onion inskillet and cook until squash is tender, about 5-10 minutes. Stir only occasionally to prevent burning.
Meanwhile, in a separate bowl, combine garlic herb seasoning, panko bread crumbs, cheese, and fried onion pieces. Transfer half of that mixture to a separate bowl and combine with the egg and heavy cream. Pour that mixture over the squash, and then sprinkle the remaining crumb mixture over the top.
Bake in preheated oven for about 15 minutes or until golden brown. Serve hot.