Funeral Potatoes

8 tablespoons (1 stick) butter
One 28 - 32 ounce bag frozen shredded hash brown potatoes
1 medium onion, finely diced
1/4 cup flour
1 cup milk
2 cups chicken broth
Kosher salt and freshly ground black pepper
1 1/2 cups grated Monterey Jack cheese
1 cup sour cream
1/2 cup grated sharp Cheddar cheese
2 cups kettle-cooked potato chips
1/4 cup grated Parmesan cheese

Preheat oven to 350 degrees. Grease a 9 x 13 baking dish with 1 tablespoon of the butter. Take the potatoes out of the freezer while preparing the rest of the ingredients.

Heat a large, deep skillet over medium-high heat, melt 6 tablespoons of the butter.  Add the onions and cook stirring occasionally, until the onions start to soften (3 to 4 minutes). Sprinkle the flour over the onions and stir to incorporate. Cook for a minute or 2 to cook the flour but do not let it brown. Whisk in the milk, making sure to remove the lumps. Add the broth and whisk again. Bring the mixture to a simmer and allow to thicken, about 3 minutes. Season to taste with salt and pepper. Turn off the heat and stir in the Monterey Jack, sour cream and cheddar. Add the hash brown potatoes and mix. Transfer to the prepared baking dish.

Melt the remaining 1 tablespoon butter in a small pan. Crush the potato chips in a bowl with the Parmesan. Pour the melted butter on the potato chip mixture to coat. Sprinkle the potato chip crumbs over the top of the potatoes. Cover with foil and bake 20 minutes then remove the foil and continue baking until golden brown and bubbling, about 15 minutes more. Let rest for 15 minutes before serving.