1 ½Tablespoonsunsalted butter(plus more to butter the baking dish)
1 ½Tablespoonsall-purpose flour
¼teaspoonsea salt
⅛teaspoonground black pepper
1cupmilk
4ouncescheddar cheese(1 cup shredded)
2mediumrusset potatoes(about 1 pound)
½yellow onion(about 1/4 cup sliced)
Instructions
Add the butter, salt and pepper to a medium-sized saucepan. Heat over medium heat until melted.
Add the flour and whisk to combine. Continue stirring for one minute.
Stir in the milk and continue to cook until the mixture has thickened.
Add the grated cheese and continue to stir until completely melted. Remove from heat and set aside.
Thinly slice the potatoes into 1/4-inch slices using a sharp knife or mandolin.
Shave or thinly slice the onion.
Layer 1/2 of the potato slices on the bottom of 2) 8-ounce or 1) 1/2 quart buttered baking dish. Top with the onion slices. Top with the remaining potato slices.
Carefully pour the cheese sauce over the potatoes making sure it finds it’s way into the cracks and crevices between the potatoes.
Place the baking dishes on a silpat/parchment paper lined baking sheet. Fold a crease into a large sheet of aluminum foil and place it over the top of the baking sheet.
Bake in a preheated 400 degree oven for one hour. Remove the foil very carefully, there will be a lot of steam, and continue baking for 20 to 30 minutes more until the sauce is bubbly and golden, and the potatoes are tender. Allow to cool for 5 to 10 minutes then serve,
Notes
I used unsweetened CashewMilk and sharp cheddar cheese to keep mine lactose-free. Yours will be even creamier if using whole milk.
I left the skins on the potatoes because that is where all of the nutrients are. Feel free to peel the potatoes for picky eaters, it won’t hurt anything.