Preheat & organize: Preheat your oven to 425°F (220°C). Arrange a large roasting tray and a heavy ovenproof skillet (cast iron preferred). High heat is key for crisp skin and golden potatoes — 425°F gives enough oven energy to brown without drying the chicken.

Prep the chicken (pat dry & season): Pat each thigh very dry with paper towels (moisture is the enemy of crisp skin). Gently slide your fingers under the skin to loosen it from the meat and tuck one thyme sprig under each skin (this places the herb oil right against the meat during roasting). Season both sides liberally with sea salt and cracked black pepper; sprinkle a small pinch of crushed red pepper over each if you like heat. Rub about 1/2 tbsp olive oil over each thigh so the skin browns evenly.

Halve and parboil the potatoes: If any potatoes are markedly larger, halve them so pieces are uniform. Place potatoes in salted cold water, bring to a simmer, and cook 8–10 minutes until just tender when pierced (you want them cooked through but not falling apart). Parboiling shortens roast time and roughens exteriors — both help produce a crisp, crackly crust when roasted.

Rough up and oil potatoes: Drain potatoes and return to the pot. Shake the pot a few times (or toss with a fork) to roughen the surfaces — those torn edges are where crispiness forms. Toss potatoes with 3 tbsp olive oil, 2 smashed garlic cloves, salt and pepper; spread them in a single layer on the roasting tray leaving room for the chicken. The garlic will release flavor into the oil and potatoes as they roast.

Sear chicken skin-side down: Heat a large ovenproof skillet over medium-high heat with 1 tbsp olive oil. When shimmering, place thighs skin-side down and press gently so skin contacts the pan — sear 4–6 minutes until deeply golden and much of the fat has rendered. Searing gives the skin a head start and creates complex Maillard flavors that roasting alone won’t achieve. You can skip this step if you’re short on time, but your skin won’t be as crisp or flavorful.

Arrange for roasting: Transfer seared thighs (skin-side up) to the roasting tray among the potatoes. Nestle the remaining smashed garlic cloves and two lemon halves (cut side down) into the tray — roasting lemons concentrate sweetness and make a terrific finishing squeeze. Scatter the remaining thyme sprigs and spoon any chicken fat left in the skillet over the potatoes for extra flavor.

Roast until done: Roast at 425°F (220°C) for 25–30 minutes depending on thigh size, turning the tray once halfway if the potatoes are browning too quickly. Cook until the chicken reaches 74°C (165°F) at the thickest point or juices run clear and the skin is deep golden. High heat plus rendered fat from the thighs will finish crisping the potatoes and caramelize the lemon and garlic into an intensely savory bed.

Make the mint-parsley gremolata while the chicken roasts: In a small bowl combine 4 tbsp finely chopped parsley, 4 tbsp finely chopped mint, 2 tsp lemon zest, 1 small clove garlic minced (optional if you want a sharper bite), a pinch of salt, and 1 tsp olive oil to bind. The gremolata is a bright herb finishing mix — the lemon zest and mint cut through the roasted fat and refresh the palate.

Blanch and butter the peas: While the roast finishes, bring a pot of salted water to a boil. Add the peas and cook 2 minutes until bright green and just tender. Drain and immediately plunge into ice water to stop cooking and preserve color. Drain again and toss with 5 g (1 tsp) butter, a small squeeze of lemon juice, salt and pepper. The quick blanch locks in sweetness and the butter gives a silky sheen that complements the gremolata.

Rest the chicken: Remove the tray from the oven and transfer thighs to a cutting board. Tent loosely with foil and rest 5–8 minutes so juices redistribute — cutting too soon lets flavorful juices escape. Meanwhile, return the tray to oven for 2–3 minutes if you want potatoes extra-crisp.

Finish and plate: Squeeze the roasted lemon halves over the chicken and potatoes for bright acidity. Arrange potatoes and peas on plates, place a thigh skin-side up, spoon pan juices over everything, and finish with a generous sprinkle of mint-parsley gremolata. The gremolata adds an herbal, citrusy contrast that lifts the whole dish.

Serve: Offer extra lemon wedges and a small bowl of flaky sea salt at the table. Serve immediately — this dish is best enjoyed hot with the contrast of crisp skin, tender meat, and bright herb topping.