1. Melt butter in a large nonstick skillet over medium-high heat. Add onions, vinegar, Worcestershire sauce, and 1 teaspoon salt and cook, stirring occasionally, until liquid has evaporated and onions are very dry with darkened edges, about 10 minutes. Add baking soda and continue to cook, stirring frequently, until onions are dark brown, 2 minutes. Scrape onions into a medium bowl and cool at least 10 minutes.
2. Add sour cream, yogurt, chives, remaining 1 teaspoon salt, and the pepper to bowl with onions. Stir to combine, then cover and refrigerate at least 1 hour and up to 2 days. Garnish with more minced chives before serving.
Source: Hannaford fresh Magazine, December 2019