Before starting, wash and dry all produce. Lightly oil the grill. While potatoes cook, preheat the grill to 500°F over medium-high heat. Halve potatoes (quarter if larger). Add potatoes, 2 tsp salt and enough water to cover (by approx. 1 inch) to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat. Once boiling, reduce heat to medium. Simmer uncovered, until fork-tender, 10-12 min. Drain and return potatoes to the same pot, off heat.

Meanwhile, core, then cut apple into 1/4-inch matchsticks. Add mayo, half the mustard, half the vinegar and 1/4 tsp (1/2 tsp) garlic salt to a large bowl. Season with pepper, then stir to combine. Add apples, cabbage and carrots, then toss to combine. Set aside.

Combine maple syrup, remaining mustard and remaining vinegar in a medium bowl. Pat chicken dry with paper towels. Season with remaining garlic salt and pepper. Drizzle 1/2 tbsp (1 tbsp) oil over top.

Add chicken to the grill. (TIP: Arrange chicken tenders across grill grates to stop them from slipping through!) Close lid and grill, flipping once, until chicken is cooked through, 4-5 min per side.** When chicken is cooked through, brush one side with maple-mustard glaze, then flip, glazed-side down. Grill for 30 sec, then repeat on other side. Transfer chicken to the same medium bowl. Toss with any remaining maple-mustard glaze.

Add 1 tbsp (2 tbsp) butter to the pot with drained potatoes. Season with salt and pepper, to taste, then gently toss to melt butter and coat potatoes, 1-2 min.

Divide grilled chicken, buttery potatoes and apple slaw between plates. Drizzle any remaining glaze from the bowl over chicken.