Preheat and prep the pan: Set your oven to 160°C (140°C fan). Place a large sheet pan in the oven to heat up while you prepare everything. A hot pan is the secret to a crisp, golden underside.

Make the ranch butter: In a small bowl, mash together the softened butter, minced garlic, dried dill, dried parsley, onion powder, smoked paprika, cayenne (if using), lemon juice, and a generous pinch of salt and pepper. Mix until it forms a fragrant, speckled paste. The smell at this point is already intoxicating—earthy and fresh all at once.

Prepare the chicken: Pat the chicken completely dry with kitchen paper. This step is non-negotiable; any moisture left on the skin will steam rather than crisp. Using your fingers, gently loosen the skin over the breast and thighs. Slide the herby butter underneath the skin, spreading it evenly. Rub any remaining butter all over the outside of the chicken. The skin should feel slick and cool to the touch, with little bumps of butter visible underneath.

Tumble the potatoes: In a large bowl, toss the halved potatoes with the olive oil, a good pinch of salt, and a few cracks of black pepper. They should look glossy and evenly coated.

Assemble on the pan: Carefully remove the hot sheet pan from the oven. Scatter the seasoned potatoes in a single layer around the edges, leaving a clear space in the centre. Place the chicken, breast-side up, in the middle. Tuck the lemon halves and thyme sprigs around the chicken. The pan will hiss and sputter as the potatoes hit the hot metal—that’s the sound of good things to come.

Roast low and slow: Place the pan in the oven and roast for 1 hour. The butter will melt and seep into the potatoes, while the skin slowly tightens and begins to turn a pale gold. You'll hear a gentle, steady sizzle.

Crank the heat for the finish: After 1 hour, increase the oven temperature to 220°C (200°C fan). Roast for another 15-20 minutes. The skin will deepen to a rich, burnished amber, and you'll hear the crackling intensify. The potatoes should be soft enough to pierce easily with a fork, with crispy, wrinkled edges. The chicken is done when the juices run clear, and the thickest part of the thigh reaches 74°C on a meat thermometer.

Rest before carving: Remove the pan from the oven and let it rest for 10-15 minutes. This is a vital pause. The juices inside the chicken need time to redistribute, ensuring every slice is moist and tender. The potatoes will also firm up slightly, making them even more deliciously chewy.