Step 1

Preheat oven to 350° convection or 375° conventional.

Step 2

Scrub, peel, and slice 4 medium russet potatoes— 1 1/2 to 2 pounds. Slice thin—about 3/8 inch thick. A mandolin is recommended if you have one. If you use a mandolin, please follow the manufacturer's safety instructions.

Step 3

Chop 1 small onion. Chop or slice your ham into bite-size pieces.

Step 4

Over medium-high heat, in a medium saucepan, melt 4 tablespoons of butter and add the onion. Cook until clearing—about 3-4 minutes.

Step 5

Sprinkle in 4 tablespoons flour and mix well. Continue to cook and whisk for about 2 minutes until browning some.

Step 6

Add 3 cups of milk slowly while continuing to whisk. Whisk and cook until thickening well—about 3-4 minutes. During this part, add 1 teaspoon salt and 1/2 teaspoon black pepper.

Step 7

Prep a 9 by 13 inch casserole dish with a coat of butter.

Step 8

Add about 1/3 of the sliced potatoes—top with 1/3 of the ham, 1/2 cup of shredded cheese, and 1/3 of the sauce. Repeat twice, but with the top layer, add the cheese last and double to a full cup.

Step 9

Cover with aluminum foil.

Step 10

Bake for 90 minutes, then uncover and cook another 20-25 minutes until nicely brown and bubbling. Allow to sit for about 10 minutes before serving—do not skip this step.