Adjust racks to middle and top positions and preheat oven to 450 degrees. Wash and dry produce. Bring a large pot of salted water to a boil.

Trim green beans if necessary.

Once water is boiling, add cavatappi to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. 

Reserve 1 cup pasta cooking water, then drain.

While pasta cooks, pat chicken* dry with paper towels and season all over with half the harissa powder (all for 4 servings), salt, and pepper. 

Heat a drizzle of oil in a large pan over medium-high heat. Add chicken; cook until browned and cooked through, 3-5 minutes per side. 

Transfer chicken to a medium bowl; let rest at least 3 minutes. (You'll finish the chicken in the next step.)

While chicken rests, in a second medium bowl, combine BBQ sauce, honey, and ¼ cup plain water (⅓ cup for 4 servings). Heat pan used for chicken over low heat. Add sauce mixture; bring to a simmer, then cover. 

Transfer chicken (and any juices) to bowl used for sauce. Using two forks, shred chicken into bite-size pieces. 

Increase heat under pan with sauce to medium low. Transfer chicken to pan; stir to evenly coat. Cover and cook, stirring occasionally, until sauce has thickened, 8-10 minutes.

Meanwhile, place gouda in a large bowl; tear into small pieces. Add white cheddar cheese, cream sauce base, half the Fry Seasoning, ¼ cup reserved pasta cooking water, 1 tsp salt, and pepper (½ cup pasta cooking water and 2 tsp salt for 4 servings); stir to combine. 

In a third medium bowl, combine panko, yellow cheddar cheese, remaining Fry Seasoning, and a drizzle of oil. 

In an 8-by-8-inch baking dish (9-by-13-inch baking dish for 4 servings), combine drained cavatappi, cheese sauce, and 2 TBSP butter. Top with panko mixture. Bake on middle rack until topping is browned and sauce is bubbling, 10-15 minutes. 

Meanwhile, toss green beans on a baking sheet with a drizzle of oil, salt, and pepper. Roast on top rack until browned and tender, 8-10 minutes.

Halve and toast buns.

Fill buns with saucy chicken.

Divide sandwiches, green beans, and mac 'n' cheese between plates and serve.