Step 1

Preheat your pellet grill to 225°, following to factory instructions.

Step 2

In a medium saucepan over medium-low heat, melt your butter. Whisk in the flour until there are no more lumps. Cook, whisking frequently, for 5 minutes. Add the garlic for the last 2 minutes of cooking the roux.

Step 3

Stir in the cream, salt, onion & garlic powders, and black pepper.

Step 4

Heat over medium heat until simmering, stirring continuously, until thickened.

Step 5

Add in the whole milk, if necessary. (The sauce should be the consistency of gravy. Thick, but pourable. Only add the milk in if it is thicker than that.)

Step 6

Coat a 2.5 quart baking dish with butter. Layer half of your sliced potatoes inside, and put half the cheeses on top of the potatoes. Pour half the sauce over the potatoes.

Step 7

Layer the rest of the potatoes on top, top with the remaining cheese, and pour the rest of the sauce on top. Sprinkle the top with the panko breadcrumbs.

Step 8

Smoke for one hour at 225°. Turn the heat up to 325°. Cook for an additional hour, or until the potatoes are fork tender. (How long this takes depends on the type of potato, how thick they are sliced, and how thick they are layered.)

Step 9

Optional - brown the top of the casserole under the broiler if the grill doesn't do the trick! You can also pre-toast the crumbs before putting them on the casserole if you would rather do it that way!

Step 10

Let cool for 5-10 minutes before serving.