Preheat the oven to 425°F degrees. Rinse and cut veggies to be about the same size so they cook evenly and place them in the bottom of the roasting pan. Drizzle olive oil over veggies and sprinkle with salt and pepper. Place a roasting rack on top.
Remove the giblets from the inside of the chicken; you can roast the heart and liver in the bottom of the pan if you like it or just throw away. Give the chicken a quick rinse and pat dry with paper towels, the dryer the better! Remember to wash your hands any time you handle raw chicken.
Cut the lemon in half, place one half inside the chicken and save the other for juice. Peel and smash garlic cloves and place inside the chicken. Add 1-2 sprigs of rosemary inside the cavity and 2-3 spring on with the vegetables in bottom of the pan.
Place chicken on the rack, tuck in legs and wings (or tie them if you are really feeling fancy). Drizzle olive oil on top and sprinkle with salt and pepper. Take the second half of lemon and squeeze juice over top of chicken (no seeds please).
Place the roasting pan in the oven and roast for 1 hour and 20 minutes. The chicken is done when the juices run clear between the thigh and leg or it's at the internal temp you would like (165 is safe for chicken). Once done, remove the pan from the oven and cover with foil for 10-15 minutes to rest before cutting and serving.