To caramelize the onions:

1. Add 1 tablespoon of butter to a large skillet and turn the heat to medium. Allow the butter to melt and swirl it around the pan.
2. Add the very thinly sliced onions and stir them into the butter so they’re evenly coated. Sprinkle with salt and sugar and stir until distributed.
3. Keep the heat at medium and cook for 20 minutes. After 20 minutes, ensure the pan isn’t too dry. (If the pan looks dry or the onions look like they may stick to the pan, add a splash of water.)
4. Turn the heat down slightly to medium-low and continue to cook for 10-15 minutes, until the onions are a deep brown color.
5. Let the onions cool slightly, then transfer to a cutting board. Finely chop the onions, then set them aside. The onions can be prepared a day in advance.

To prepare the dip:

1. In a medium-sized bowl, combine the plain Greek yogurt, softened cream cheese, and mayonnaise. Stir until well combined.
2. Add the soy sauce, garlic powder, and chopped onions. Add salt to taste, if needed.
3. Cover and transfer the bowl to the fridge. Allow the dip to chill for about 30 minutes. This dip can be prepared up to 2 days in advance.