Melt the butter with the olive oil in a skillet over medium heat. Once it’s melted, add the onions and stir. Season the mixture with ½ teaspoon salt and turn the heat down to medium low. Allow the onions to cook low and slow until nicely caramelized, about 20-25 minutes. Make sure to stir pretty frequently so they don’t burn. It helps to have a lid handy to cover the pan for a few seconds if the onions are looking dry.
Once the onions are a deep golden brown, season well with black pepper and add in the minced garlic. Turn the heat off and allow the pan to cool before adding in the cream.