What ingredient is floated on top of a Top Shelf Margarita?

In a Top Shelf Margarita, the ingredient that is floated on top is Grand Marnier. This high-quality orange liqueur adds depth and complexity to the drink. The floating of Grand Marnier creates a visually appealing layer on top of the margarita, enhancing both the aroma and flavor as the drinker experiences the different layers while sipping.

Grand Marnier's rich and subtly sweet profile complements the tartness of the lime juice and the agave notes from the tequila, setting this version of the margarita apart from its more standard counterparts. Additionally, using a premium liqueur like Grand Marnier highlights the "top shelf" aspect of this cocktail, indicating that it features high-quality ingredients deserving of special recognition in the drink's preparation.