Preheat the Traeger: Set your Traeger Ironwood grill to 400°F and let it preheat.
Prepare the Pie Crust: Roll out the pie dough in a glass pie plate. Crimp the edges and pierce the bottom with a fork or knife a few times.
Cook the Pie Crust: Place the pie crust in the preheated Traeger and cook for about 20 minutes, until golden brown. Pull from the grill and allow to cool briefly.
Prepare the Tomatoes: While the pie crust is cooking, slice the tomatoes into 3/4 inch thick slices and sprinkle generously with salt on both sides. Place tomato slices on paper towels to soak up some of the juices.
Mix the Filling: In a bowl, combine mayonnaise, grated Cabot Vermont Sharp Cheddar cheese, grated Cabot Mozzarella cheese, chopped green onions, fresh basil, and Garlic Junkie seasoning. Stir to mix well.
Assemble the Pie: Spread 1/3 of the mayo/cheese mixture on the bottom of the prepared pie crust. Arrange the tomato slices in a single layer in the pie crust, cutting as necessary to fill the pie as much as you can. Top with the remaining 2/3 of the cheese mixture and spread evenly.
Cook on the Traeger: Place the assembled pie on the Traeger set at 375°F. Cook for 30 minutes, rotating as necessary to ensure even cooking. Bake until the top is bubbly and brown (about 45 minutes total).
Serve: Remove the pie from the grill and allow to cool before slicing and serving. Enjoy alongside a Traeger-grilled steak for a perfect summer meal.