Butternut Squash, Potato & Sausage Gratin

2 lb. butternut squash, peeled and sliced into 1/8 inch thick slices
2 lb. Yukon Gold potatoes, peeled and sliced into 1/8 inch thick slices
2 lb. mild Italian sausage, browned, crumbled and drained
3 cups heavy cream
1 1/2 cup grated parmesan cheese
1/4 cup minced garlic
3 T. fresh rosemary, chopped

Preheat oven to 350. In a large greased casserole, drizzle heavy cream across the bottom. Layer and overlap squash slightly to cover the bottom of the pan. Drizzle with cream, sprinkle with cheese, garlic, and rosemary. Top with about ¾ cup sausage. Repeat with potatoes and alternate with squash, you should have 5 or 6 layers. Cover with homemade breadcrumbs and cover with foil. Bake for 1 hour and check. The cream should be boiling and the potatoes and squash should be fork tender. If not, recover and continue in 10-minute increments until done. Uncover and increase temperature to 425 and bake for 15 minutes.