3 chicken halves, breast and rib bone bones intact (1 1/2 to 1 3/4 pounds)
Kosher salt and freshly ground pepper
1 tablespoon extra virgin olive oil
1/2 tablespoon unsalted butter
5 to 6 twigs of thyme
Partially release the chicken halves, remove the wing, the spine and the thigh. Rinse and let dry. Cool, uncovered, at least 30 minutes to dry the skin.
Season the chicken with salt and pepper on both sides. Heat a large non-stick pan (preferably cast iron) over medium heat and add the oil and the butter. Put the chicken halves, the skin down, into the pan and disperse the thyme around them. Wrap a slightly smaller pan with foil and place on the chicken. Place a large brick or 2 to 3 heavy doses in the pan to weigh it.
Boil the chicken 3 to 5 minutes, then remove the top pan and check the skin; Adjust the heat and turn the pan as needed so that the skin tans evenly. Replace the upper pan and continue until the skin is golden and crisp, and the chicken is cooked about three-quarters of the passage, 20 to 25 minutes. Remove the upper pan and carefully turn the chicken. Cook, uncovered until the chicken is cooked, 8 to 10 minutes. Transfer to a cutting board and allow to rest for 5 minutes. Cutting each piece in half.