My signature cupcake is a chocolate cupcake with raspberry filling. I used to pipe the filling into the cupcake with a large tip and pastry bag...but now I have a cupcake corer! Using the pastry bag method is fine, but the amount of filling in each cupcake depends on how deep the tip goes into the cake and how much pressure you put on the bag. Some cupcakes get more filling than others.
The cupcake corer allows each cucpake to get the same amount of filling and you end up with a very beautiful presentation!
Bonus: You get to eat the mini donut holes of cake that are left over!