Heat oven to 375 degrees F. Prep potatoes and cheese.

Heat a stainless steel skillet on medium heat. Melt butter and add flour. Using a whisk, mix and whisk the flour constantly for 3 to 4 minutes. Whisk in heavy cream and milk slowly and cook for 4-6 minutes, whisking the entire time. Add salt, pepper and white pepper to taste. Whisk in cheese until completely melted. Remove from heat and pour the cheese sauce into a measuring cup with a spout.

Pour about 1/4 cup of the cheese sauce into the bottom of a baking dish (I used a 14.5 by 8 inch one). Layer overlapping slices of potatoes on top the cheese sauce and pour some cheese sauce on top. Spread with a spoon and continue layering potatoes and cheese sauce until you have no more sauce. I had about 5 or 6 layers of potatoes in mine - it may different for you depending on how big your baking dish is.

Bake at 375 degrees F covered with foil for about 20 minutes. Remove foil and continue baking for about 45-60 minutes or until potatoes are cooked through (use a butter knife or fork and poke through the potatoes, if it's soft, they're ready). If needed, turn on the broiler to brown the top of the potatoes.

These potatoes reheat very well and taste even better the next day. Store in a tightly sealed container for 2-3 days.