Mix filling ingredients together.
Cover and refrigerate until ready to use (at least a couple of hours).
When ready to serve, use a ziploc bag (cut the corner) or pastry bag with 1/2 inch star tip. Pipe filling into one end of a shell to the center, then into other end. Repeat with remaining shells and filling. Dust with confectioners' sugar, and serve immediately.
Let the filling smoosh out of each end of the shells, just a tad.
Some people sprinkle powdered sugar on top right before serving or dip the ends into chocolate shavings.