This is a wonderful alternative to mashed potatoes for Thanksgiving and can be made the night before throughout the year when you have a busy schedule. Day-old gratin is always better and only requires you to reheat it in the oven or if you have a makeshift steam table. This recipe is a combination of potato and two different sliced squash which is prettier to present than an off-white colored blob.
Use a 9" x 13" baking dish which should serve 10-12, or 8 very hungry people.
2 large Russet Potatoes, peeled and sliced very thin
1 Acorn Squash, peeled and sliced very thin
1 Butternut Squash, peeled and sliced very thin
2 Tbl. fresh Thyme with leaves de-stemmed
12-16 oz. grated Gruyere cheese depending on how cheesy you like your casseroles
1 tea. Salt
1 tea. fresh cracked Black Pepper
8 oz. Butter, divided in half + extra to prepare baking dish
1 pint Heavy Cream
Preheat oven to 325-degrees.
Place sliced potatos and squash in a large mixing bowl along with fresh thyme, grated Gruyere, salt and pepper. Mix well to ensure the mix is evenly coated.
Grease your baking dish with butter or a nonstick baking spray.
Pour half the potato, squash, cheese mixture in the baking dish. Dot with half of the 8 oz. of butter. Pour the remaining potato, squash, cheese mixture into the baking dish and dot with the remaining 4 oz of butter. Pour heavy cream into the baking dish and bake for approx. 45 minutes until bubbling and beautifully browned on top. If your casserole is browing too quickly before mixture begins to bubble, cover with foil until finished baking.
DO NOT SERVE IMMEDIATELY or you will have a soupy mess. The butter and cream have to absorb into the vegetables (20 minutes).
Add you favorite breadcrumb topping before baking
Add french fried onions topping before baking
Add more cheese to the top before baking.