Start the preparation for this simple oven roasted chicken by preheating the oven to 425°.
Before handling the chicken, prepare everything you need to make the chicken. If you do not have a cast iron skillet, use a sheet pan lined with parchment paper.
In a small bowl, mix softened butter, minced garlic, rosemary, lemon juice, and a bit of salt and black pepper. Use a fork to mix the compound butter.
Cut lemons into wedges, and slice red onions into thick rounds.
Line the pan with thick slices of onion. You are going to rest the chicken breast-side up on top of the onions. This will lift the chicken up a bit in the pan and let the heat circulate around the whole bird to cook evenly and get a good crisp all the way around.
Remove the chicken from the package. Check the inside of the body cavity, and remove any neck or giblets that are inside. ( Some companies do not put giblets in the package, so don’t be too worried if you don’t find anything.)
Use a few paper towels to pat the chicken dry all around. You need a nice dry skin to get the butter and seasoning to adhere, and to get crispy skin.
Next, place the chicken on top of the onions breast side up. Rub the compound butter over every part of the chicken. Be sure to pull the legs and wings back to get seasoning in every nook and cranny. Place lemons into the cavity of the chicken. Then, pull the legs together and tie with kitchen string or use a barbecue skewer and thread it through the backs of the chicken legs. (I never remember to pick up butcher’s twine. The skewer works just fine. If you have neither, you can still cook the chicken. The underside of the legs just might not get as well browned.)
Place the pan of chicken into a preheated 425° oven. Cook at this temperature for 20 minutes. Then turn the oven down and finish cooking at 350°. A higher temperature in the beginning will start to crisp the outer skin and guarantee a golden brown bird. It will also seal moisture in to get super juicy meat.
Once the chicken has reached 165°, remove it from the oven. Place the whole roast chicken on a cutting board to rest and carve.
Carve the rested chicken by removing the legs and thighs at the joint. They should come away from the body by simply twisting them upwards towards the breast and using a butcher knife to help separate the joint.
Remove the wings the same way.
Then remove the breast meat. Bring your knife in as close to one side of the breast bone as possible and cut away one whole side of the breast. Then cut the breast into thick slices. Do the same to the other side.