I haven made a few Instructables that will lead you easily to this final product. You will need:
1 X recipe of Pate a Choux
1X recipe of Pastry Cream
Dark or milk chocolate, per your preference.
Additionally, you will need several pastry piping tips. A long injection tip will do nicely, a plain round one in the smallest circumference that you have, and another tip two times as big. Tip # 802/Wilton 12. If you do not have a tip, I will give you an alternative way to make and fill your eclairs.
Make sure your pastry cream is properly chilled before starting this Instructable. I recommend having this dessert ready no more than 4 hours before you are going to serve it.
Step 1: Mise en Place!
Make your Pate a Choux and place it in a pastry bag fitted with your tip # 802/Wilton 12. If you do not have a pastry bag, you can use a coupler and a ziploc. If you have neither bag nor tip, use a small cookie scoop. If you have no scoop, use two spoons.
I use a coffee press to hold my pastry bag as I fill it. Anything cylindrical and hollow should do the trick.
Put your heavy cream in a pot. If you are using blocks of chocolate, chop and measure 4oz. If you are using chips or pastilles, skip the chopping and just measure. Set aside.
Have a small bowl of water ready.
Prepare your sheet pans with parchment paper. Place a dab of Choux batter under the paper at each corner to prevent it from moving around as you begin to pipe. If you have a convection oven this will also prevent the paper flying around and ruining your work.
Heat your oven to 350F/175C degrees.