4 skinless, boneless chicken breasts
3/4 pound small red-skinned potatoes, halved
2 sprigs fresh rosemary, plus 1 Tbsp leaves
1 clove garlic, smashed
Pinch of red pepper flakes
Juice of 2 lemons (squeezed halves reserved)
1 Tbsp extra-virgin olive oil
2 tsp salt
Preheat oven to 450 degrees F. In a saucepan, cover the potatoes with cold water and salt the water. Bring to a boil over medium-high heat and cook until tender, about 8 minutes. Drain and set aside.
Pile the rosemary leaves (1 Tbsp), garlic, 2 tsp salt and the red pepper flakes on a cutting board, then mince and mash into a paste using a large knife. Transfer the paste to a bowl. Stir in the juice of 1 lemon and the olive oil. Add the chicken and turn to coat.
Heat a large cast-iron skillet over medium-high heat. Add the chicken, cover and cook until browned, about 5 minutes. Turn the chicken; add potatoes to the skillet and drizzle with the juice of the remaining lemon.
Add the rosemary sprigs and the squeezed lemon halves to the skillet; transfer to the oven and roast, uncovered, until the chicken is cooked through, about 25 minutes.