2 tablespoons unsalted butter, at room temperature
2 tablespoons olive oil, plus more for drizzling
2 tablespoons chopped preserved lemon
2 garlic cloves, minced
Leaves from 1 rosemary sprig, chopped
Kosher salt and freshly cracked black pepper
Using a knife or kitchen shears, cut down along first the right side and then the left side of the chicken’s backbone to remove it. On a clean surface, flip the chicken over so the skin side (uncut side) is up. Place the palms of your hands on the upper breast of the chicken and push down until you hear the breast bone crack. Allow the chicken to rest at room temperature for up to 30 minutes before cooking.
Preheat the oven to 450°F.
In a small bowl, combine the butter, olive oil, preserved lemon, garlic, rosemary, 1 teaspoon salt, and 1/2 teaspoon black pepper. Mix until fully combined. Using a spoon, scoop up 1 tablespoon of the butter mixture and tuck it under the skin over each chicken breast. Rub the remaining butter all over the chicken.
Heat a large cast-iron skillet over high heat and drizzle with olive oil. When hot, place the chicken skin-side down in the pan. Sprinkle the underside of the chicken with salt and pepper. Sear until the skin is golden brown, 3 to 5 minutes. Flip the chicken over. Place the skillet into the oven and roast the chicken until the internal temperature of the breast is 160°F and the skin is golden brown, 45 to 50 minutes.
Remove the skillet from the oven and let the chicken sit for 15 minutes. Carve and serve.