Which ingredient is added to a tall green tea frappuccino before blending?

The addition of 2 scoops of matcha powder to a tall green tea frappuccino before blending is essential for the drink's signature flavor and character. Matcha powder, made from finely ground green tea leaves, provides the drink with its characteristic green color and a distinctly rich, earthy flavor that is central to the beverage's identity. Without this key component, the frappuccino would lack its intended taste, making the inclusion of matcha powder crucial for a proper green tea frappuccino experience.

In contrast, the other ingredients mentioned do not align with the traditional preparation of a green tea frappuccino. Mocha sauce, strawberry juice, and coffee base serve different purposes in other drinks and would alter the flavor profile of a green tea frappuccino, potentially diluting the experience that customers expect when ordering this specific beverage. Thus, the use of matcha powder is what truly defines the drink.