Preheat the oven to 450 degrees F.

Season the chicken on both sides with the salt and white pepper. Set a cast iron pan over high heat and add 2 teaspoons of the olive oil to the pan. Swirl the pan to evenly coat and lay the seasoned chicken half, skin-side down in the pan. Sear until golden, about 3 minutes and place the pan in the oven. Bake until the chicken is fully cooked through, about 17 minutes.

While the chicken roasts, combine the butter, garlic and thyme in a small bowl and use a fork to combine. When the chicken is removed from the oven, place on the wooden trivet, and turn over with a spatula. Spread the thyme-garlic butter over the skin of the chicken, drizzle with lemon juice and serve immediately.

In a cast iron pan or a small oven-proof skillet, heat the olive oil over medium-high heat. Add the potato slices and onion slices. Top with thyme sprigs and butter. Season with salt and pepper, to taste. Place the pan in the oven and cook the potatoes for about 15 to 20 minutes, until sizzling and fork-tender. Serve immediately.