Prep Time: 15 mins
Cooking Time: 1 hour 35 mins
Serves: 10 – 12
Place potatoes and squash in a large pot of water and bring to a boil over high heat. Cook until potatoes and squash are not yet quite tender, 25 minutes. Drain, gently rinse in cool water and set aside until potatoes are cool enough to handle.
Meanwhile, in a medium sauté pan, melt 4 tablespoons butter over medium heat. Add sage and thyme, stirring occasionally until butter is brown and fragrant, about 3 minutes. Add onion and sauté until tender, about 3 minutes. Add garlic, stirring about 2 minutes longer. Transfer to a medium bowl and set aside.
Heat oven to 350°F. Generously butter a 9-by-13-inch baking dish or two 9-inch pie plates, place on a baking sheet and set aside.
Add shredded Low Moisture Whole Milk Mozzarella, shredded Aged Parmesan, Whole Milk Ricotta, 1 cup of the heavy cream, salt and pepper to the onion herb mixture and stir until well combined. Set aside for assembly.
Peel and slice potatoes and squash into 1/4-inch thick slices. Keep potatoes and squash in separate piles to make it easier to arrange in baking dish by color.
For assembly, divide baking potatoes, squash and sweet potatoes in half. Starting at one of the short ends of the 9-by-13-inch baking dish, arrange by alternating baking potatoes, sweet potatoes and squash allowing the second row to slightly overlap the previous row. Repeat until half of the potatoes and squash have been arranged in the baking dish. Sprinkle the arranged potatoes and squash with ½ of cheese mixture. Repeat layering in the same pattern and top with remaining cheese mixture. Pour the remaining 1 cup of heavy cream over the top and garnish with sage leaves.
Bake until potatoes and squash are cooked through, the cream is mostly absorbed, top is golden brown and the cheese is bubbling, 45 minutes to 1 hour.
Let cool for 5 minutes, serve and enjoy!