In large skillet, heat the oil over medium heat. Add the chopped onions and ¼ teaspoon of salt.
Cook and stir often until the onions are caramelized to a golden brown color. About 30-40 minutes.
Remove onions from heat and cool to room temperature.
To Make Dip
In small bowl, combine Greek yogurt, mayonnaise, garlic powder, ground white pepper and salt.
Stir in cooled onions.
Cover and refrigerate the dip for at least 2 hours or overnight before serving.
Serve with fresh vegetables or potato chips.
MAKE AHEAD TIP:This recipe is make ahead! Because you have to chill it for at least two hours to let the flavors blend well. You can also make the caramelized onions the day before and add to the rest of the ingredients when you are ready.MONEY SAVING TIP:Look for store brand Greek yogurt to save money. I like to buy the Kirkland Organic plain Greek Yogurt from Costco as it seems to be the best value per ounce but my local grocery store has some good options too.