Ready your ingredients and preheat oven and grill/pan. Put the diced root vegetables in a large bowl. Preheat the oven to 425°F (220°C) — this high heat will caramelize edges quickly without drying the interior. If using a grill, preheat to medium-high; if using a heavy skillet (cast-iron) for the chicken, set it on medium-high so it’s smoking-hot when you sear.

Make the lemon-herb marinade/dressing (split the lemon juice). From the 60 ml (4 tbsp) lemon juice total, reserve 1 tbsp (15 ml) for the salad dressing and set aside. In a bowl whisk together the remaining 45 ml (3 tbsp) lemon juice, 3 tbsp (45 ml) olive oil, 3 tsp chopped rosemary, 2 tsp chopped thyme, 2 minced garlic cloves, 1/2 tsp sea salt and a few grinds of cracked black pepper. This acidic marinade brightens and tenderizes the chicken while the oil carries flavor and prevents sticking.

Marinate the chicken briefly. Pat the 720 g chicken dry with paper towel (dry surface = better sear). Place chicken in a shallow dish or zip-top bag and pour marinade over, turning to coat. Marinate at room temperature 15–20 minutes (no more than 30) — the lemon will start to 'cook' proteins if left too long and can make texture mealy. Short marination gives flavor and tenderizing without over-acidifying.

Toss the root vegetables with oil, herbs and salt. Drizzle the vegetables with the remaining olive oil (about 3 tbsp / 45 ml), the remaining chopped rosemary and thyme, the remaining 2 minced garlic cloves, 1/2 tsp sea salt and a few grinds of cracked pepper. Toss to coat evenly; a light coating of oil helps promote even caramelization and prevents the beets/parsnips from drying out.

Roast the root vegetables. Spread the vegetables in a single layer on a rimmed baking sheet (use two sheets if crowded — crowding steams instead of roasts). Roast at 425°F (220°C) for 25–30 minutes, turning once halfway through to ensure even browning. Roast until edges are deeply caramelized and a knife meets little resistance — this deep caramelization transforms sugars to savory-roasty notes.

Prepare the lemon-herb salad dressing. Whisk the reserved 1 tbsp (15 ml) lemon juice with 3 tbsp (45 ml) olive oil, 1 tsp minced fresh thyme, a pinch of salt and a few grinds of pepper. Taste and adjust — the small amount of lemon keeps the arugula bright without overwhelming the roasted vegetables.

Grill or pan-sear the chicken to develop color and seal juices. Remove chicken from marinade and let excess drip off (discard used marinade). Season each breast lightly with the remaining 1/2 tsp sea salt and cracked pepper. For grill: oil grates and grill 5–6 minutes per side over medium-high heat until an instant-read thermometer registers 160°F (71°C) in the thickest part; residual heat will carry it to 165°F (74°C) while resting. For stovetop: sear in a hot cast-iron skillet with a tablespoon olive oil, 4–5 minutes per side, finishing in a 375°F (190°C) oven if needed. Searing creates the Maillard crust which adds deep savory flavor.

Rest and slice the chicken. Transfer cooked breasts to a cutting board and loosely tent with foil; rest 6–8 minutes. Resting lets the juices redistribute so slices stay moist rather than spilling juices onto the plate.

Assemble the warm salad. When vegetables are done and still warm, transfer them to a large bowl and toss with the baby arugula and the lemon-herb dressing. The arugula will wilt slightly from the heat — this softens bitterness and ties the hot and cold elements together.

Plate and finish. Slice chicken breasts thinly on the bias and fan them over the warm roasted root-arugula salad. Drizzle any pan juices sparingly over the chicken for extra flavor and a gloss finish. Finish with a light shower of flaky sea salt and extra cracked black pepper to taste.

Serve immediately. Encourage diners to combine a bit of chicken, roasted root veg and peppery arugula in each forkful so they experience the contrasting textures—charred chicken, sweet-roasted veg, and crisp-aromatic greens.