02Meanwhile, prepare the lettuce and peas: Combine the wine, red onion, bay leaf, peppercorns and a pinch of salt in a saucepan; simmer over medium heat until the mixture is syrupy and just coats the bottom of the pan. Whisk in the butter cubes, a few at a time, to thicken the sauce and give it a shine. Season with salt and pepper and keep warm. (Remove the peppercorns and bay leaf before serving.)03Place the peas in a small pot of salted boiling water until heated through; drain. Toss the peas, lettuce and beurre blanc (warm butter sauce) in a bowl until the lettuce wilts slightly. Serve with the chicken.