In a large pan, melt butter over medium heat. Add onions, salt and pepper. Cook, stirring occasionally, until onions begin to soften {about 5 minutes}.

Stir in the sugar, scraping the brown bits off the bottom of the pan. Cook, stirring occasionally, for an additional 15-20 minutes until the onions are golden brown. Transfer to cutting board and coarsely chop.

In a large bowl, combine the Greek yogurt, sour cream and Philidelphia cream cheese. Mix well. Stir in worcestershire sauce, 2 slices of crumbled bacon and onions. Mix well. Top with remaining slice of crumbled bacon. Refrigerate until about 20 minutes prior to serving.