In a large skillet over medium heat, melt the 4 tablespoons of unsalted butter.
Once the butter is melted, add the chopped sweet onions. Stir to coat them with the butter.
Sprinkle in at least ½ teaspoon of kosher salt and pepper. This will help draw out the moisture from the onions and enhance their flavor.
Cook the onions, stirring occasionally, for about 25-30 minutes until they are golden brown and caramelized. If they start to brown too quickly, lower the heat to prevent burning.
In a mixing bowl, combine the caramelized onions with 1 cup of sour cream (or Greek yogurt), ½ cup of mayonnaise, and 1 teaspoon of garlic powder. Stir until everything is well mixed.
Taste your dip and adjust the seasoning if necessary. You may want to add more salt, pepper, or garlic powder based on your preference.
Cover the dip and let it chill in the refrigerator for at least an hour to allow the flavors to meld. Just before serving, top with fresh herbs like parsley for a pop of color.
