Wash and dry all produce. Remove stems and large ribs from kale and discard. Chop leaves into bite-sized pieces. Zest one lemon until you have 1 tsp zest, then cut into halves. Add kale, zest, and juice from one lemon half to a medium bowl. Season with salt and pepper. Massage leaves with hands until tender, then set aside.

Bring 1 cup water, stock concentrate, and a pinch of salt to a boil in a small pot. Pick tarragon leaves from stems; discard stems. Roughly chop leaves. Mince 1 clove garlic (we sent more). Halve grape tomatoes lengthwise. Cut remaining lemon into wedges.

Once stock is boiling, add couscous to pot. Remove from heat, cover, and set aside.

Heat a drizzle of olive oil in a large pan over medium-high heat. Pat chicken dry with a paper towel, then season all over with salt and pepper. Add to pan and cook until browned on surface and no longer pink in center, 6-10 minutes per side. Remove from heat and let rest 5 minutes.

While chicken cooks, make the dressing: in a small bowl, whisk together mustard, brown sugar, 1 tsp tarragon, juice from remaining lemon half, 4 TBSP olive oil, and salt and pepper (to taste). In another small bowl, make the chimichurri: combine remaining tarragon, garlic, chili flakes (to taste), a squeeze of lemon, and a large drizzle of olive oil. Season with salt and pepper.

Fluff couscous with a fork, then season with lemon juice, salt, and pepper to taste. Toss kale in bowl with tomatoes and 1 TBSP dressing. Divide couscous, kale mixture, and chicken between plates. Spoon over remaining dressing. Serve with chimichurri for dipping and lemon wedges on the side.