Start by thinly slicing the onions.

In a skillet, melt the butter with the olive oil over medium heat.

Add the sliced onions and sprinkle with salt.

Cook the onions for about 25-30 minutes, stirring occasionally until they turn golden brown.

Once the onions are caramelized, stir in the black pepper and garlic powder.

Remove the skillet from heat and let the onions cool for about 10 minutes.

In a mixing bowl, combine sour cream and mayonnaise.

Fold in the cooled onions and chives (if using).

Serve immediately or refrigerate for a bit to let the flavors meld.