This classic French eclair recipe is easy to follow and makes the most dreamy eclairs. They're filled with light and airy pastry cream and topped with chocolate ganache glaze.
Make the pate a choux: Preheat oven to 400°F/204°C. Line two sheet pans with parchment paper or silicone baking mats.
Place milk, water, butter, sugar, and salt into a medium-sized pot. Heat on medium heat until the butter is melted and the sugar and salt are dissolved, stirring occasionally. Add the flour all at once and mix with a large spoon until a dough paste is formed. Mix the dough ball with a large spoon against the bottom and sides of the pot for about a minute, which gently cooks the flour. You'll know it's done when the dough appears slightly dry and easily pulls away from the sides of the pot. Remove from heat and place dough into the bowl of an electric mixer fitted with the paddle attachment.**
Whisk the eggs together in a small bowl. Turn the mixer on medium speed and slowly and gradually add the eggs a bit at a time (about the amount of one egg). Allow the mixer to incorporate all the egg before adding more. When you have the amount of one egg left, add it bit by bit until the dough reaches a soft, shiny, pipeable consistency. I usually have about half an egg leftover, but it just depends on how much liquid evaporates when cooking the choux on the stovetop.
Place the dough into a piping bag fitted with a round or star tip with an opening 1/2-inch in diameter. Pipe 4-inch cylinders 3 inches apart using even pressure, lifting upwards and backwards at the end to bring the tails upwards. Do not start and stop piping as you pipe each cylinder. To remove the pointy tails, wet your finger and gently press them down before baking.
Bake for 15 minutes then, keeping the eclairs in the oven, lower the temperature to 350°F/177°C for 12-15 minutes, until the eclairs are golden brown on top. Do not open the oven as they bake. Once fully baked, remove eclairs from the oven and allow to cool completely on a cooling rack before filling.
Make the pastry cream: In a medium bowl, whisk together egg yolks and sugar just until pale yellow and creamy, then whisk in the cornstarch. Set aside. In a medium saucepan, heat milk and vanilla until it starts to steam. Gradually pour the hot milk into the egg mixture while simultaneously whisking constantly until smooth (Tip: place a wet towel or cloth underneath the bowl with the dry ingredients to prevent it from moving around).
Transfer mixture back into saucepan. Cook over medium-low heat, whisking constantly and vigorously so that the eggs won’t curdle, until the mixture thickens. Allow the mixture to boil slightly for 30 seconds (you'll see bubbles popping up through the thick cream), then remove from heat and strain using a fine mesh strainer. Transfer to a medium heatproof bowl and add butter. Allow the pastry cream to cool slightly, then place a piece of plastic wrap directly on top to prevent it from forming a skin. Place in the fridge to cool completely. Alternatively, you can cool the pastry cream using an ice bath.***
Once the pastry cream is completely cooled, whip heavy cream to soft-medium peaks. Fold into the pastry cream using a rubber spatula and store in the fridge until ready to use.
Make the chocolate ganache glaze: Place chocolate in a medium heat-proof bowl. Set aside. In a small saucepan over medium heat, bring cream just to a boil. Immediately pour cream over chocolate and let sit without stirring for 1-2 minutes. Then, whisk together until smooth. You can also do this in the microwave by placing both chocolate and cream in a microwave-safe bowl. Microwave in 30-second increments, mixing between each increment, until melted and smooth. Allow to slightly cool before topping eclairs. You want it to still be a viscous consistency, but thick enough that you can get a nice topping on each eclair without it being too thick.
Fill and top the eclairs: Use a sharp knife to poke two holes in opposite ends of the bottoms of each eclair. Fill a pastry bag with the chilled pastry cream and deposit into each eclair through the holes. Dip the tops into the ganache and place right-side-up onto a sheet pan. Place in the fridge so the ganache can set.
Eclairs are best eaten the day they're made, but will stay good in the fridge for up to 2 days. If you have leftover pastry cream, it makes an amazing pudding on its own. Store in the fridge with plastic wrap placed directly on top so it doesn't form a skin. When ready to use, place pastry cream into small glasses or ramekins and serve with fresh berries and chocolate sauce.
*I prefer using bread flour for eclairs because it gives them more structure and prevents them from getting super soggy. However, feel free to substitute with all-purpose flour if that's what you have on hand, just keep in mind that the eclairs will be softer.
**If you don't have a mixer, you can add the eggs by hand or use a handheld mixer. If adding by hand, use a whisk and mix the eggs into the dough vigorously. The dough will looked separated and curdled at first, but keep whisking until the eggs are fully incorporated and the dough is smooth.
***To create an ice bath, place the bowl with the pastry cream in a larger bowl it can fit into. Fill the larger bowl with cold water and ice. Occasionally mix the pastry cream to distribute the cold, and place it in the fridge once chilled.