This is a rich, creamy and oh-so dreamy comfort food dish! A take on traditional Funeral potatoes, it's enhanced with a few punches of strong, savory flavors.
*This can be a side or main course. It serves about 12 as a side, and 6 to 8 as a main.
Preheat the oven to 375°F, and adjust a rack to the center.
Fill a large bowl with cold water. Peel and grate the potatoes and add them to the bowl of water.
Add the stock to a medium-sized pot. Remove 1 1/2 cups of the grated potatoes from the water, squeeze out as much liquid as possible with your hands, and add them to the stock. Place the pot over high heat and bring to a boil. Then cover, turn the heat to low, and simmer until the potatoes are soft, about 5 minutes. Pour this mixture into a blender and purée just until smooth, 5 to 10 seconds on high. (Alternatively, you can also use a hand immersion blender in the pot.) Set aside to cool.
Place a large sauté pan (about 14-inch), over medium heat, and add 2 tablespoons of the butter, onions and garlic. Stirring often, until the onions are soft, about 10 minutes. Mix in the prosciutto and 1 1/2 tablespoons of the rosemary and sauté for another 3 minutes.
Pour the remaining grated potatoes into a strainer, and then squeeze out as much liquid as possible with your hands, adding them to the sauté pan as you go. Add 1 more tablespoon of the butter and mix everything together. Stirring often, continue sautéing until the potatoes are beginning to turn golden, about 10 minutes.
Pour the contents of the pan into a very large mixing bowl, and let it cool slightly. Add the the stock-potato mixture, sour cream and 2 cups of the cheese. Quickly stir to combine, season to taste with salt and pepper, and then pour this into a 9 x 13 x 2-inch baking dish. Set aside.
Melt the remaining 4 tablespoons of butter, and in a small bowl, combine it with the remaining 1/2 tablespoon of rosemary and the breadcrumbs. Sprinkle this evenly on top of the potato mixture, along with the remaining 1/4 cup of cheese.
Place in the preheated 375°F oven and bake uncovered for 20 minutes. If it’s not golden on top when it’s done baking, you can place it under the broiler for about 30 seconds. Let it cool for at least 10 minutes before serve.
Time saving tips: