5-7 medium russet potatoes
2 tablespoons butter
1 clove garlic
1 tablespoon flour
1 cup cream
2 ½ cups milk
1 tablespoon Dijon
1 teaspoon salt
2 cups sharp cheddar cheese
1 cup Monterey jack cheese
Preheat grill to 350 degrees.
Cut your potatoes using a mandolin.
Butter a cast iron skillet, and arrange potatoes in a thin layer on the bottom then top with a small amount of both cheeses. Add another layer of potatoes on top then cheese. Continue adding layers until cast iron is full. Set aside.
In a saucepan, sauté the garlic in butter until fragrant. Add the chopped rosemary stir for a minute. Add flour and stir constantly until flour begins to smell slightly nutty.
Add milk and cream and increase heat, stir until liquid has reduced slightly.
Add mustard, salt, and 2 cups sharp cheddar cheese. Stir until all the cheese has melted and remove from heat.
Pour mixture over the potatoes.
Add cast iron to the grill and cook for 45-60 minute, or until potatoes are soft.