Preheat oven to 350 degrees. Remove the fat, neck, liver and gizzards from the body cavity, and then rinse and pat the chicken dry. Gently separate the skin from the flesh, running your fingers from the front to the back of the chicken and along the leg and thigh, being careful not to rip the skin or detach it from the bird.
Mix the butter, chopped basil and parsley, salt and pepper together in a small bowl. Rub half of the butter mixture under the loosened skin of one chicken; be sure to get it under the skin around the leg and thigh. Repeat with the second chicken.
Put four of the garlic cloves into the body cavity of each chicken and scatter the rest in the roasting pan. Add the lemon juice and broth. Place the chickens, breast side up, on top of the garlic and broth. Roast in the oven, basting occasionally with the pan juices, for 1 hour, or until the juices run clear when the thickest part of the thigh is pierced. Transfer the chickens to a heated platter and tent with aluminum foil to keep warm.
Pour the juices with the garlic cloves into a blender and purée, then place through a sieve into a medium-sized saucepan, pressing on the garlic skins with the back of a spoon. Bring the liquid to a simmer over medium heat, stirring occasionally, about 3 minutes, and add salt and pepper to taste. Carve the chickens and serve them drizzled with the sauce and garnished with fresh basil leaves.
Nutrition information per serving: