Averie Cooks

-1 Preheat oven to 350F and spray a 9x13-inch baking dish (or 2.5 to 3 quart baking dish) very well with cooking spray; set aside.
-1 Casserole - To a large saute pan, add the butter, and heat over medium-high heat to melt, whisk constantly.
-1 Add the flour and cook for 1 minute; whish constantly. Tips - Do not shortcut this step. First, you need to cook the flour or later on yoru casserole will have an odd raw flour taste. Secondly, this is a roux, which is what is used to help thicken the cream sauce and casserole later on, since we are not used any canned/condensed/cream-of style soups.
-1 Slowly add the milk; whisk constantly and continue to do so for about 1 minute, or until the sauce begins to thicken slightly.
-1 Add the sour cream and whisk to combine.
-1 Add both cheeses, all three seasonings, salt, pepper, and whisk constantly until the cheese has melted.
-1 Add the hash browns and stir to combine and coat evenly.
-1 Turn the mixture out into the prepared pan; set aside momentarily.
-1 Topping - To a large bowl, add the Corn Flakes. Tip - I crush the corn flakes in my hand, a heaping handful at a time. They don't have to be in a fine dust or too small. Therefore crushing them in my hand is the fastest, easiest, and creates no extra dishes or appliances to wash.
-1 Evenly drizzle the melted butter over the cereal and toss to evenly coat, noting that it won't seem like there's quite enough butter, but it's enough to just moisten some of the flakes, which is that's needed.
-1 Evenly add the topping over the casserole.
-1 Bake for about 25 minutes, or until the lightly golden browned and bubbling around the edges, or as desired. Tip - I rotate my pan once midway through for even baking and browning. All ovens vary, so just keep an eye on your casserole to make sure the corn flakes aren't getting overly browned nor are burning.
-1 Serve immediately. Leftovers will keep airtight in the fridge for up to 5 days, or in the freezer for up to 3 months. Note that the Corn Flakes will not stay crispy on the leftovers or for anything that's been frozen. They absorb the moisture from the cheesy potatoes below and that's just the way it is. See below for make-ahead tips.