Wash and dry all produce. Heat a grill for medium heat. (TIP: If cooking indoors, heat oven to 450 degrees.) In a small bowl, combine barbecue sauce, 2 tsp vinegar, 2 tsp mustard, and 1/4 tsp chipotle powder (we’ll use more of the vinegar and mustard later; add a pinch more chipotle for extra heat).

Pat chicken legs dry with a paper towel and rub all over with 1 tsp olive oil each. Season all over with plenty of salt and pepper. Add to grill and cover. Cook until no longer pink throughout, 35-40 minutes, flipping halfway through. TIP: If cooking indoors, roast chicken on a baking sheet in oven about 25 minutes.

Cut potatoes into 3/4-inch cubes. Cut four pieces of kitchen foil, each about 12 inches long. Place potatoes on foil, adding about a quarter to each, and sprinkle with Southwest spice, a large pinch of salt, and a large drizzle of olive oil. Toss to coat. Tightly seal foil around potatoes, making four packets.

Place potato packets on grill and cook until tender, 25-35 minutes (or roast in oven about 35 minutes). Keep sealed until ready to serve. While chicken and potatoes cook, halve, peel, and mince shallot. Thinly slice garlic. Roughly chop cilantro. Heat a large drizzle of olive oil in a large pan over medium-high heat. Add green beans and a large pinch of salt. Cook until just tender, about 5 minutes.

Add a large drizzle of vegetable oil to same pan, then toss in garlic and minced shallot. Cook until fragrant, about 30 seconds. Stir in remaining vinegar and mustard. Cook 30 seconds more. Remove from heat, then add 2 TBSP butter and half the cilantro, stirring to melt. Once chicken is cooked, increase grill heat to medium high.

Brush chicken all over with half the barbecue sauce mixture. Cover and grill 2 minutes more, flipping once. (TIP: If cooking indoors, brush after 25 minutes, then roast 10 minutes more.) Remove chicken from heat and brush with rest of sauce mixture. Divide chicken, potatoes, and green beans between plates. Garnish with remaining cilantro.