2 1/4 cups whole milk
6 large egg yolks
2/3 cup sugar
1/3 cup cornstarch
1 vanilla bean, split lengthwise
1 cup cream (whipped before filling eclairs)
In medium bowl, whisk together 1/2 cup milk, egg yolks, 1/3 cup sugar, and cornstarch.
Transfer remaining 1 3/4 cups milk to heavy medium saucepan. Scrape in seeds from vanilla bean; add pod. Sprinkle remaining 1/3 cup sugar over, letting sugar sink undisturbed to bottom. Set pan over moderate heat and bring to simmer without stirring.
Whisk hot milk mixture, then gradually whisk into egg yolk mixture. Return to saucepan over moderate heat and cook, whisking constantly, until pastry cream simmers and thickens, about 1 minute. Remove from heat, discard vanilla pod, and whisk cream until smooth. Transfer to bowl and press plastic wrap directly onto surface. Chill until cold, about 4 hours.
Pate a Choux
Preheat the oven to 425 degrees F.
Place the water, butter, sugar, and salt in a saucepan. Place over medium-high heat and cook until the butter is completely melted and the mixture is simmering.
Add in the flour all at once, and continue to cook, stirring, for about 5 minutes, or until the dough gathers itself into a ball and a film begins to form on the bottom of the pot.
Transfer the mixture to a mixing bowl, and beat on medium speed.
Drop in the eggs, one at a time, while continuing to beat. Allow each egg to become fully incorporated, before adding the next (about 30 seconds to a minute).
Pipe or spoon the dough onto parchment-lined baking sheets, allowing about 3 inches in between each puff.
Bake time can range from 20-40 minutes, depending on size. Remove from the oven when they are puffed, golden brown, hollow, dry, and light.
Whip cream until stiff peaks form. Fold into chilled pastry cream until smooth. Fill pastry bag for piping into cooled shells. Use a chop stick or something similar to poke three holes in the bottom of the the cooled puffs. Pipe into eclairs. Melt chocolate by putting chips into microwave for 30 seconds at a time until smooth. Dip eclairs on one side. Let set and serve. Refrigerate if not eating immediately.
I used this recipe for the Pate a Choux.