Chicken with Truffles and Champagne Sauce

Preparation Whisk flour, salt, and pepper in shallow bowl. Coat chicken pieces in seasoned flour; transfer to rack. Let stand 15 minutes. Coat with flour again; return to rack. Melt butter with oil in heavy large skillet over medium heat. Working in batches, add chicken and sauté until brown, about 5 minutes per side. Transfer chicken to plate. Add shallots to skillet and sauté until golden, about 2 minutes. Add Champagne and bay leaf and bring to boil, scraping up browned bits. Return chicken and any accumulated juices to skillet. Cover and simmer until chicken is just cooked through, about 15 minutes. Meanwhile, cook green beans in large pot of boiling salted water until crisp-tender, about 2 minutes. Using slotted spoon, transfer to bowl of ice water. Cool quickly, then transfer beans to paper towels to drain. Return water to boil. Add celery root and carrots and boil 1 minute. Drain; transfer vegetables to ice water to cool quickly, then transfer to paper towels to drain. Pat all vegetables dry. Transfer chicken to platter; tent with foil to keep warm. Place egg yolks in small bowl. Gradually whisk in 3 tablespoons chicken cooking liquid. Place same skillet over medium-low heat. Whisk in yolk mixture. Cook until sauce begins to thicken, stirring constantly, about 2 minutes (do not allow mixture to boil). Add vegetables and truffle, if desired, to sauce and cook until heated through, about 2 minutes. Spoon sauce with vegetables around and over chicken and serve.

Preparation Whisk flour, salt, and pepper in shallow bowl. Coat chicken pieces in seasoned flour; transfer to rack. Let stand 15 minutes. Coat with flour again; return to rack. Melt butter with oil in heavy large skillet over medium heat. Working in batches, add chicken and sauté until brown, about 5 minutes per side. Transfer chicken to plate. Add shallots to skillet and sauté until golden, about 2 minutes. Add Champagne and bay leaf and bring to boil, scraping up browned bits. Return chicken and any accumulated juices to skillet. Cover and simmer until chicken is just cooked through, about 15 minutes. Meanwhile, cook green beans in large pot of boiling salted water until crisp-tender, about 2 minutes. Using slotted spoon, transfer to bowl of ice water. Cool quickly, then transfer beans to paper towels to drain. Return water to boil. Add celery root and carrots and boil 1 minute. Drain; transfer vegetables to ice water to cool quickly, then transfer to paper towels to drain. Pat all vegetables dry. Transfer chicken to platter; tent with foil to keep warm. Place egg yolks in small bowl. Gradually whisk in 3 tablespoons chicken cooking liquid. Place same skillet over medium-low heat. Whisk in yolk mixture. Cook until sauce begins to thicken, stirring constantly, about 2 minutes (do not allow mixture to boil). Add vegetables and truffle, if desired, to sauce and cook until heated through, about 2 minutes. Spoon sauce with vegetables around and over chicken and serve.