Preheat the oven to 425 degrees F.
1. Remove the chicken giblets. Rinse the chicken inside and out and pat the outside dry. Stuff the cavity with the bunch of thyme and all the garlic. Brush the outside of the chicken with the ghee and sprinkle with salt and pepper. Tie the legs together with kitchen string and tuck the wing tips under the body of the chicken.
2. Place the onions, carrots, and potatoes in a roasting pan. Add salt, pepper, rosemary sprigs and chicken broth. Toss to combine. Spread around the bottom of the roasting pan and place the chicken on top.
3. Roast the chicken for 1½ hours, or until the juices run clear when you cut between a leg and thigh. Remove the chicken and vegetables to a platter and cover with aluminum foil for about 20 minutes. Slice the chicken onto a platter and serve it with the vegetables.