Which ingredient is used to sweeten Coffee Royale?

In Coffee Royale, sugar is the traditional and most common ingredient used to sweeten the drink. Sugar dissolves well in hot liquids, making it an ideal choice to enhance the flavor of coffee without overpowering it. Moreover, using sugar allows bartenders to maintain control over the sweetness level, as they can adjust the quantity based on personal preference or the specific profile of the coffee being used.

While honey, simple syrup, and maple syrup can also serve as sweeteners, they each offer distinct flavors that may alter the intended taste of Coffee Royale. Therefore, sugar is recognized as the classic sweetening agent for this particular beverage, aligning with standard practices in cocktail and coffee preparation.