Step 4: Fill 'Er Up
The eclair shells should be cooled by now. To fill them, either poke a small hole on the end or two in the bottom (flat side) of the eclair. You can do this using the tip itself or a paring knife. With the tip inside the eclair, pipe in some pastry cream. I caution not to be zealous with this procedure because your eclair could explode. Also, for cleaner presentation, do not overfill. The pastry cream will end up coming out if you do. Fill each eclair in this manner.
For the cream puffs of Profiteroles, you can fill them the same way.
If you do not have a pastry bag and tip, cut the tops off of your shells whether they be eclairs or cream puffs. Using a spoon, fill the cavity with pastry cream. One of the pictures shows the cream puff as it should be cut and the darker picture illustrates the cavity inside the shell that you will be filling.
Once you have filled each shell by your preferred method, arrange them on which ever platter or plate you will be serving them on. This is crucial for the product if you have cut the top off, as it minimizes finger prints on the ganache and messy presentation. Once you have arranged them, test the ganache to make sure it has not cooled and begun to set. If it has, gently heat it again. Dip the top of each product in the ganache, gently shake off the excess and then place it on the plate again, or on top of its mate.
You are done. If you would like, you can keep these uncovered in the fridge until serving time. If you will not be serving them for several hours but want them to be closer to room temperature, then keep them in the fridge to avoid time and temperature abuse (the pastry cream is perishable) and remove them about an hour before serving.You will need to time this to coincide with the starter or the entree depending on how fast or slow you want to take things.
If you have leftover shells you do not need to keep them in an airtight container. You can use them one more day, but they do not keep well for longer. You want your baked goods to be enjoyed as fresh as possible, but if you have a hankering the morning after, just dip the unfilled shells in chocolate and eat with a little spoonful of pastry cream. Baked Choux tends to be hygroscopic and will suck up any moisture around it making it floppy and rubbery.