This rich sauce is a great addition to yogurt, ice cream or as a topping for pancakes.
Place all the ingredients in a medium saucepan and stir to blend. Cook over medium heat, stirring frequently, until the sauce is hot and has thickened, about 5 minutes. Let the sauce cool for 10 minutes, then stir in the Cointreau, if using.
Serve hot or cold, as you like. Store unused sauce in the refrigerator for up to 10 days.