Preheat the Oven:
Preheat your oven to 425°F (220°C).
Prepare the Chicken:
Pat the chicken dry with paper towels to ensure a crispy skin. Rub the chicken all over with olive oil, then season with garlic powder, onion powder, dried thyme, salt, and pepper. Place the halved garlic head inside the cavity of the chicken.
Roast the Chicken:
Place the chicken in a roasting pan and roast for 1 hour and 15 minutes, or until the chicken reaches an internal temperature of 165°F (75°C) when checked at the thickest part of the thigh. Baste the chicken with its juices every 20 minutes for a golden, crispy skin.
Make the Asiago Gravy:
While the chicken is roasting, make the gravy. In a small saucepan, melt butter over medium heat. Once melted, whisk in the flour to create a roux. Cook for about 2 minutes until the mixture is golden and bubbly. Gradually whisk in the chicken broth, ensuring there are no lumps. Bring to a simmer and cook for about 5 minutes, until the gravy thickens. Stir in the heavy cream and grated Asiago cheese, continuing to stir until the cheese has melted. Season with salt and pepper to taste.
Rest the Chicken:
Once the chicken is done, remove it from the oven and let it rest for 10 minutes before carving.
Serve:
Carve the chicken and plate it. Pour the Asiago gravy over the chicken and garnish with freshly chopped parsley.