1. Melt 1 tablespoon butter in a small saucepan over medium heat, then add shallot and cook, stirring frequently, until softened, 2 to 3 minutes.
2. Stir in sparkling wine, scraping up any browned bits with a wooden spoon, and cook until thickened and syrupy, 2 to 3 minutes. Add broth, vinegar, and thyme and cook until liquid has reduced and is thick enough to coat the back of a spoon, 5 to 7 minutes.
3. Remove from heat and whisk in remaining 3 tablespoons butter until incorporated, then season with salt and pepper to taste. Remove thyme sprig before serving.
Source: Hannaford fresh Magazine, December 2021