Preheat your Yoder Smokers YS640s Pellet Grill to 425ºF, set up for indirect grilling.
Place the potatoes on a sheet pan and coat in a thin layer of Saica Sicilian Extra Virgin Olive Oil and season with Cattleman’s Grill Trail Dust All Purpose Seasoning. Transfer the sheet pan to the main cooking grate. Roast until tender when pierced with a toothpick or knife, about 60-75 minutes.
Place the bacon on a wire rack over a foil lined sheet pan. Place on the second shelf of the grill and cook until crisp, about 45 minutes. Remove from the rack and dice or crumble.
Trim the tip of the head of garlic (opposite the roots) to expose the cloves. Place on a sheet of foil. Drizzle with Saica Sicilian Extra Virgin Olive Oil. Wrap tight in the foil and transfer to the grill. Cook until the cloves are tender, about 45 minutes.
While the potatoes are still warm, scoop out the flesh. Place in a pan. Chop a handful of the skins and reserve for later.
Squeeze the roasted garlic cloves from their paper and add to the flesh of the potatoes along with the sour cream, butter, white cheddar, milk, half of the bacon and half of the green onions. Add about two tablespoons Cattleman’s Grill Trail Dust All Purpose Seasoning. Mash with a handheld potato masher to desire consistency. Taste and adjust seasoning with salt, as needed.
Spray a Lodge Cast Iron Casserole Dish (or 9x13 baking dish) with Cornhusker Kitchen Spray Duck Fat. Transfer the potato mixture to the dish and level the top. Sprinkle the sharp cheddar evenly over the top.
Bake until the cheese is melted and slightly browned on top, about one hour.
While the Twice Baked Potato Casserole cooks, take a couple of tablespoons of the bacon grease from the foil lined pan and warm in a small skillet. Add the handful of diced potato skins and cook until crispy.
Serve the Twice Baked Potato Casserole topped with the remaining remaining green onions and bacon, as well as the crisped potato skins and a drizzle of sour cream.