1stick(8 tablespoons) unsalted butter plus more for greasing the baking dish
3poundsrusset potatoes, peeled
Kosher or fine sea salt
Freshly ground black pepper
12ounces Hatch diced chiles, hot or mild, un-drained
1 ½cupsheavy cream
4cupsgrated Mexican blend cheese
2green onions
¼cupcilantro
Instructions
Place the stick of butter into the freezer while you slice the potatoes. Prepare a large bowl of ice water.
Preheat oven to 350°F. Butter a deep 9 by 12-inch baking dish.
Slice the potatoes about ⅛-inch thick (a mandoline works well for this) and place the potatoes directly into the ice water.
Remove butter from freezer and grate with the large holes of a box grater.
Take about one third of the potatoes, pat dry, and layer into the bottom of the prepared baking dish. Sprinkle with a generous pinch of salt and pepper. Sprinkle one third of the butter over the potatoes, spoon one can of the chiles over the top, pour over ½ cup cream, and top with 1 cup of grated cheese. Repeat with two more layers topping with 2 cups cheese for the top layer.
Bake for 65–75 minutes or until golden brown on top and the potatoes are tender. Let sit for 15 minutes.
Finely mince the green onions and cilantro and sprinkle over the top.