1Make the beurre blanc: Bring wine, vinegar, shallots, thyme, and bay leaf to a boil in a small saucepan over medium heat. Continue to boil until liquid has evaporated, 3 to 4 minutes. Stir in cream and boil until liquid has reduced by half, 4 to 5 minutes. Reduce the heat to low. Whisk in one piece butter until melted; repeat with remaining butter. Do not allow sauce to simmer, or it may separate.
2Strain sauce through a fine sieve into a heat-proof bowl. Stir in chives, lemon juice, salt, and pepper. Set the bowl into a larger container full of hot water to keep warm until needed.