Ingredients:

  • 1 cup (240 ml) water
  • 1/2 cup (113g) unsalted butter, cut into cubes
  • 1/4 teaspoon salt
  • 1 cup (120g) all-purpose flour
  • 4 large eggs, at room temperature
  • 2 cups (473 ml) whole milk
  • 1/2 cup (100g) granulated sugar
  • 1/4 cup (30g) cornstarch
  • 1/4 teaspoon salt
  • 4 large egg yolks
  • 2 tablespoons (28g) unsalted butter
  • 1 teaspoon vanilla extract
  • 6 ounces (170g) semi-sweet chocolate, finely chopped
  • 1/2 cup (120ml) heavy cream

Instructions:

  1. Combine water, butter, and salt in a saucepan and bring to a boil.
  2. Add flour all at once and stir vigorously until a smooth dough forms and pulls away from the sides of the pan.
  3. Transfer the dough to a mixing bowl and let cool slightly.
  4. Gradually add the eggs, one at a time, beating well after each addition until the dough is smooth and glossy. It should form a 'ribbon' when lifted.
  5. Preheat oven to 400°F (200°C). Line baking sheets with parchment paper.
  6. Transfer the choux pastry to a piping bag fitted with a large round tip.
  7. Pipe 4-inch (10 cm) long strips of dough onto the prepared baking sheets, leaving space between each.
  8. Bake for 15 minutes at 400°F (200°C), then reduce the oven temperature to 350°F (175°C) and bake for another 20-25 minutes, or until golden brown and puffed up. Important: Do not open the oven door during baking, or they may collapse!
  9. Turn off the oven and prop the oven door open slightly with a wooden spoon. Allow the éclairs to cool completely in the oven to prevent them from deflating.
  10. Heat milk in a saucepan until just simmering.
  11. Whisk together sugar, cornstarch, and salt in a separate bowl.
  12. Whisk in egg yolks until smooth.
  13. Temper the egg yolk mixture by slowly whisking in a small amount of the hot milk.
  14. Pour the tempered mixture into the saucepan with the remaining milk and cook over medium heat, whisking constantly, until the cream thickens and comes to a boil.
  15. Remove from heat and whisk in butter and vanilla extract.
  16. Pour the pastry cream into a bowl, cover with plastic wrap pressing directly onto the surface to prevent a skin from forming, and refrigerate for at least 30 minutes to chill.
  17. Place chopped chocolate in a heatproof bowl.
  18. Heat heavy cream in a saucepan until just simmering.
  19. Pour the hot cream over the chocolate and let stand for 1 minute.
  20. Whisk until smooth and glossy.
  21. Using a small serrated knife, make small holes in the bottom of each éclair.
  22. Transfer the chilled pastry cream to a piping bag fitted with a small round tip.
  23. Pipe the pastry cream into the éclairs until they are filled.
  24. Dip the top of each éclair into the chocolate ganache, letting the excess drip off.
  25. Place the éclairs on a wire rack until the ganache is set.