In a large pot, add the cream of soups and roughly 2 1/2 cups of milk, and slowly whisk to bring it together. Continue cooking on medium heat, and add the butter. Get a large bowl ready because you will add the potatoes and combine everything in this bowl before transferring it to your large casserole dish. To the potatoes add it all in, reserving a cup or so of the cheese to add in later, and mix well.
Preheat your oven to 350 degrees. Butter a large casserole dish. Add the bowl of potatoes to the casserole dish and cook for roughly 2 hours, covered. Add the remaining cheese to the top, and place under the broiler to crisp up the cheese and potatoes for a few minutes.
Remove from the oven, and let cool for about five minutes as these are piping hot. These cheesy potatoes are so good that you will probably want them not only for a snack, but also for breakfast, lunch, and dinner. These served 9 with two days of leftovers. Great for a large gathering. For a kick, top with bacon.