When you return home from the market, unwrap the chicken and remove the giblets from the cavity. Rinse the chicken inside and out and dry very well with paper towels. Remove piece of fat from the outside of the cavity. Take a heaping tablespoon of salt and a few grinds of pepper and rub it inside the cavity. If there’s any more salt left on your hands, rub it in between the skin and the breast meat. Rewrap the chicken and refrigerate until ready to cook.
Remove chicken from the refrigerator 30-60 minutes before cooking. Preheat the oven to 425 degrees.
Stuff the cavity with the lemon, thyme or rosemary and garlic.
Spread the onion slices on the bottom of a shallow roasting pan. Place the chicken on top of the onions and tie the drumsticks with kitchen twine. Brush all over with the melted butter or oil.
Scatter chopped vegetables around chicken and drizzle vegetables with oil. Sprinkle chicken and vegetables with a little salt and pepper.
Roast the chicken for 1 hour 10 minutes - 1 ½ hours or until a instant read thermometer inserted in the breast reads 160-165 degrees. Transfer to a platter or a cutting board and allow to rest about 10-20 minutes, tented with foil.
Carve and serve immediately.