Preheat the oven to 425°F. Remove giblets and neck from cavity. Using a clean, washed chicken, pat completely dry with paper towels, inside and out. Coat the entire chicken with olive oil.
Add all of the seasonings to a small bowl. Reserve 2 teaspoons of the seasoning mixture for the cavity. Season the inside of the chicken cavity with this portion.
Cut 4 tablespoons (1/4 stick) of butter into slices. Place these butter slices inside the cavity along with the celery and lemon. Reserve the rest of the butter. You'll need it later.
Tie the legs together with twine and tuck the wing tips underneath the chicken. Use the remaining seasoning all over the outside of the chicken.
Grease the bottom of a heavy bottom skillet. Place the chicken into the skillet. Slice the remaining 4 tablespoons (1/4 stick) of butter into slices. Place these butter slices in the skillet around the chicken
Place the chicken into the preheated oven and roast for 30 minutes.
After 30 minutes, add the minced garlic to the pan juices. Melt the remaining 3 tablespoons of butter and use it with the pan juices to baste the chicken. Continue cooking for 45 minutes, basting every 15 minutes.
The chicken is done when the thickest part of the thigh reaches 165°F on a meat thermometer or pierce the thickest part of the thigh with a knife. If the juices run clear, the chicken is done. Transfer the chicken to a cutting board and let it rest for 10-15 minutes before carving.