Preheat a grill or smoker to 350°F and set it up for indirect heat. If using a gas grill, place a handful of dry wood chips on a large piece of aluminum foil and fold it up into a sealed pouch. Poke holes in the pouch, then remove the grates and place the packet directly on top of a burner (before it’s on). Turn on that burner and leave the other side off. Close the grill and let it heat up and fill with smoke.
Butter a 2-2½-quart baking dish and set aside.
Bring a large pot of salted water to a boil. Add pasta and cook for 2 minutes less than the package instructs. Drain, toss with 1 Tablespoon Challenge Lawry’s Seasoned Salt Butter Snack Spread and set aside.
Melt remaining 4 tablespoons Challenge Lawry’s Seasoned Salt Butter Snack Spread in a large saucepan over medium heat. Stir in flour and cook for 1 minute. Slowly add milk, whisking constantly, until completely smooth. Whisk in cream, salt and pepper. Bring to a boil, reduce to a simmer and cook, whisking often, until thickened, 8-10 minutes.
Combine both cheeses in a large bowl and toss to fully mix.
Stir all but 1 cup of cheese into the cream mixture and whisk until smooth and melted. Remove from heat, add pasta, and toss to coat.
Pour the pasta into the prepared baking dish and scatter top with remaining cheese.
Melt Challenge Lawry’s Seasoned Salt Butter Snack Spread in a medium skillet over medium heat. Add panko breadcrumbs and cook, stirring, until golden and crispy, 8-10 minutes. Sprinkle evenly over the mac and cheese.
Place the mac and cheese on the opposite side of the grill from the smoking pouch, uncovered. Close the grill and cook for 35 minutes. Check the mac and cheese, it may need another 15-20 minutes to get bubbly and golden brown without drying out. Add another wood chip pouch, if needed, for maximum smoke flavor. Serve hot.