A pastry bag is used to portion which product?

The use of a pastry bag is most commonly associated with products that require precise application and decorative techniques. Sweet cream cheese filling is often used in pastries and desserts where a controlled amount is needed for filling and piping. The pastry bag allows for accuracy in portioning this filling into various baked goods, such as pastries or cupcakes, where visual presentation and quantity are important.

While chocolate mousse and buttercream frosting can also be piped using a pastry bag, the sweet cream cheese filling is specifically associated with filling and decorative applications in a consistent, clean manner. Pasta sauce, on the other hand, typically does not require the precision and control that a pastry bag provides, as it is usually served in larger quantities and lacks the need for decorative piping. The focus on decorative or filling applications makes sweet cream cheese filling the most fitting option for being portioned with a pastry bag.