Preheat the oven to 350°F. Brush a 12 inch cast iron skillet with olive oil OR spray a 13x9 inch dish with cooking spray. Set aside.
Cook the pasta in salted water per the package directions until al dente. Drain well and set aside.
Meanwhile, shred the pepper jack and sharp cheddar cheese and toss together.
Sauce: In a large heavy bottomed saucepan melt 1/2 cup butter over medium heat. Add flour, salt, black pepper and granulated garlic mixing until the butter is fully absorbed.
Increase the heat to medium-high and gradually whisk in the milk. Bring to a gentle simmer then immediately lower the heat, whisking constantly. Let gently bubble for 5 minutes, stirring occasionally to prevent sticking.
Add 2/3 of the cheese blend. Remove from the heat mixing until the cheese has melted.
To the pot add the drained macaroni and pulled pork, stir to combine. Pour the macaroni mixture into the dish, sprinkle the top with the reserved shredded cheese.
Crumb Topping: In a small bowl toss together the panko breadcrumbs, Parmesan cheese, granulated garlic, salt and onion powder with 2 Tbsp melted butter. Sprinkle evenly over the cheese.
Bake for 35-40 minutes or until bubbly and golden.
Serve drizzled with barbecue sauce and garnish with green onions.