Start by preheating the oven to 425 degrees (220 Celsius).
While the oven is preheating, cut the lemon into four wedges. These will be stuffed into the chicken before roasting to provide a subtle citrus flavor and aroma.
Next, prepare the chicken by adding it to roasting pan and patting it dry with paper towels.
Use your fingers to gently separate the skin from the chicken by sliding your hands under the skin, making sure to get under the legs as well.
Then, gently rub 1-2 tablespoons of butter under the skin.
Spread another 2-3 tablespoons of butter over the top of the skin in an even layer, making sure to get into all the creases and over the legs and wings.
After you've applied your butter, generously season your chicken with salt, pepper, and dried thyme.
Once seasoned, stuff the chicken with lemon wedges and fresh thyme.
Tie the legs together with cooking twine and tuck the wings under the chicken before cooking. This assures all the chicken is cooked evenly.
Once the chicken is ready to go, place it into the preheated oven and cook for 70 to 90 minutes, depending on the size of the chicken. The internal temperature should be 165 degrees (74 degrees Celsius) in the thickest part of the chicken and the liquids should be clear when it's done.
Once the chicken is done cooking, cover it with foil and let it rest for 20 minutes prior to cutting. This helps to prevent the chicken from drying out.
Serve and enjoy! Save the drippings for a great gravy!