Remove the neck, liver, and gizzards from inside the chicken cavity and discard or freeze for later use. Check out Chicken Stock - Basic Chicken Stock to learn how easy it is to make your own homemade chicken stock.
Wash and dry the chicken, place on a plate, and put into the refrigerator, uncovered, for 1 to 2 days (this dries out the skin which will give a crisper skin after roasting). Be sure to remove the chicken from the refrigerator at least 2 hours prior to roasting, to bring down to room temperature.
Preheat oven to 425 degrees F.
Rub outside of chicken with 1 tablespoon of butter. Rub inside of chicken cavity with 1 teaspoon of butter and sprinkle cavity with salt. Place chicken, breast side up, in the roasting pan. Stuff inside of the cavity with onion chunks and rosemary sprigs. Arrange carrots, potatoes, squash, and Brussels sprouts in roasting pan around outside of chicken; set aside.
In a small saucepan over medium-low heat, melt together the remaining butter, olive oil, chopped rosemary, and minced garlic, stirring until combined, and then remove from heat. Using a large spoon, drizzle the rosemary-butter mixture over chicken and vegetables until the butter mixture is all used up.
Place the roasting pan with prepared chicken and vegetables in the preheated oven. Let cook for 15 minutes. After 15 minutes, open oven door, and turn down oven temperature to 350 degrees F. Baste the chicken and vegetables with the butter and juices in the bottom of the pan. Place an aluminum foil tent loosely over roasting pan to cover chicken. Bake for 1 hour, covered with aluminum foil, making sure to baste the chicken every 20 minutes with juices from the bottom of the pan.
After 1 hour of baking, open oven door; remove and discard aluminum foil tent. Bake an additional 1 hour, continuing to baste every 20 minutes (you will see the skin start to crisp up and turn golden brown) or until chicken is done when the thigh and breast registers an internal temperature of 165 degrees F. on your meat thermometer (juices will run clear when cut with the tip of a knife).
Remove chicken from oven and transfer to a cutting board, cover with aluminum foil, and let rest for 20 minutes. Place the cooked vegetables in the turned off oven to keep warm while cooked chicken is resting.
Cut chicken into serving pieces, place on the serving platter, and place vegetables along the sides. Drizzle pan juices on top of chicken.
Makes 4 servings.
* Choose a chicken weighing around 4 pounds. I prefer organic, free range chickens as I think they taste better.
** Ok to substitute your favorite vegetables to roast.
Roasted Rosemary Garlic Chicken Recipe: https://whatscookingamerica.net/Poultry/Roasted-RosemaryGarlic-Chicken.htm