First lightly caramelize the onions by placing them in a skillet over low heat for about an hour until they are a blonde/ brown color (use a small amount of salt sprinkled at the beginning). Remove from heat and cool. Meanwhile put the strips of bacon on top of a foil covered baking sheet and cook at 400 degrees for 20 minutes or until dark brown and crispy. Once the bacon and onions are cooled down place them both in a food processor and pulse until thoroughly chopped. Take a medium sized bowl and mix the bacon onion mixture with the Mayo and sour cream. Chill and serve cold with veggies and Wheat Thins.