Bring to a boil and reduce to a simmer. Simmer for 5-6 minutes, until thickened slightly.
While the milk simmers, peel potatoes and slice thinly, about 1/8 of an inch.
Layer half of the potatoes in a 9x13 baking dish.
Sprinkle half of the cheese over the top.
Sprinkle half of the herbs over the top.
Layer the rest of the potatoes in the pan. Repeat cheese and herb layers.
Pour milk mixture over the top.
Dot the top with the butter.
Bake for 40-50 minutes, covered with foil for the first 30 minutes, until fork tender. The baking time will vary depending on your pan size, shallower pans will cook more quickly and deeper pans will take longer.
Let the potatoes rest for 15 minutes after removing from the oven, this allows the liquid to thicken.
Russet potatoes are essential for this recipe to turn out correctly. They are starchy, which allows the milk to thicken in the oven. If you use another kind of potatoes, the recipe will turn out runny. You can use any kind of cheese you want. My favorites for this recipe are gouda, parmesan, or another specialty cheese that is on the firm side. Mozzarella also works really well! It's up to you. You could also do a combination of cheese. A 3-quart or 4-quart baking dish will accommodate this recipe, a standard 9x13 is typically 3 quarts.