Season the chicken generously with salt and let it sit for 30 minutes.
Stir 2 tablespoons of kosher salt or 4 teaspoons fine sea salt into the buttermilk to dissolve.
Place the chicken in a gallon-size resealable plastic bag and pour in the buttermilk.
Seal it, squish the buttermilk all around the chicken, place in a bowl, and refrigerate.
Pull the chicken from the fridge 30-60 minutes before you plan to cook it.
Preheat the oven to 425°F (220°C), with a rack set in the center position.
Remove the chicken from the plastic bag and pat dry with paper towels.
Place the chicken in a dutch oven (without the lid), 9x13 baking pan, or shallow roasting pan.
Slide the pan all the way to the back of the oven on the center rack.
Rotate the pan so that one side of the chicken is positioned lengthwise parallel to the back of the oven.
After about 20 minutes, when the chicken starts to brown, reduce the heat to 400°F and continue roasting for 10 minutes.
Rotate the pan so the opposite side is near the back of the oven.
Continue cooking for another 30 minutes or so, until the chicken is brown all over and the juices run clear when you insert a knife down to the bone between the leg and the thigh. Should be 165° on a meat thermometer.
When the chicken’s done, remove it to a platter and let it rest for 10 minutes before carving and serving.