For the chicken: Combine the olive oil, garlic and herbs in a very large bowl. Add the chicken and coat with the marinade. Cover and refrigerate 2 hours or overnight. Preheat oven to 400 degrees. Truss the chickens and season to taste with salt and pepper. Brush with the marinade. In a hot skillet, sear the breast sides 3 to 5 minutes until golden. Place in the oven and roast for 10 minutes. Reduce the heat to 350 degrees and continue roasting, basting with the marinade and pan juices, until the chicken is cooked through and browned, about 30 minutes more. Remove from the oven and let rest.
For the sauce: In large saute pan, heat the butter and olive oil over high heat until almost smoking and saute the shallot until caramelized, about 3 minutes. Add the wine and reduce until almost dry. Add the stock and the roasted garlic and cook until reduced by half. Sprinkle with salt and pepper. Remove from the heat and strain into a saucepan. Whisk in the butter. Spoon over chicken and drizzle with truffle oil.
For the potato puree: Place basil, pine nuts and garlic and oil in a food processor and process until smooth. Add the cheese and salt and pepper to taste. Pass the warm cooked potatoes through a ricer into a large bowl. Add 1/4 cup of the herb puree, milk and butter. Mix until smooth, season with salt and pepper to taste.