Ingredients:

  • 1 cup (240ml) water
  • 1/2 cup (113g) unsalted butter, cut into cubes
  • 1/4 teaspoon salt
  • 1 cup (120g) all-purpose flour, sifted
  • 4 large eggs, at room temperature
  • 2 cups (473ml) whole milk
  • 1/2 cup (100g) granulated sugar
  • 1/4 cup (30g) cornstarch
  • Pinch of salt
  • 4 large egg yolks
  • 2 tablespoons (28g) unsalted butter, cut into cubes
  • 1 teaspoon vanilla extract
  • 4 ounces (113g) semi-sweet chocolate, finely chopped
  • 1/2 cup (118ml) heavy cream
  • 1 tablespoon (14g) unsalted butter

Instructions:

  1. Combine water, butter, and salt in a saucepan. Bring to a boil.
  2. Remove from heat and add flour all at once. 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 it cool slightly (about 5 minutes).
  4. Beat in eggs one at a time, ensuring each is fully incorporated before adding the next. The dough should be smooth and pipeable.
  5. Preheat oven to 400°F (200°C). Line baking sheets with parchment paper or silicone mats.
  6. Fill piping bag with choux pastry.
  7. Pipe 4-inch (10cm) long strips of dough onto the prepared baking sheets, spacing them evenly.
  8. Bake for 15 minutes, then reduce the oven temperature to 350°F (175°C) and bake for another 20-30 minutes, or until golden brown and puffed up. Do not open the oven door during baking!
  9. Turn off the oven and crack the door open slightly. Let the éclairs cool in the oven for 30 minutes to prevent collapsing.
  10. Transfer to a wire rack to cool completely.
  11. In a saucepan, heat the milk until it's almost simmering.
  12. In a separate bowl, whisk together the sugar, cornstarch, and salt.
  13. Whisk in the egg yolks until pale and smooth.
  14. Slowly pour a little of the hot milk into the egg yolk mixture, whisking constantly to temper the eggs.
  15. Pour the egg mixture back into the saucepan with the remaining milk.
  16. Cook over medium heat, whisking constantly, until the pastry cream thickens and bubbles.
  17. Remove from heat and stir in the butter and vanilla extract.
  18. Pour the pastry cream into a bowl, cover with plastic wrap (pressing the wrap directly onto the surface to prevent a skin from forming), and refrigerate for at least 30 minutes, or until completely chilled.
  19. Place chopped chocolate in a heatproof bowl.
  20. Heat the heavy cream in a saucepan until simmering.
  21. Pour the hot cream over the chocolate and let it sit for 1 minute.
  22. Stir until smooth and glossy. Stir in the butter.
  23. Once the éclairs are completely cool, use a small knife or piping tip to poke holes in the bottom of each éclair.
  24. Fill a piping bag with the chilled pastry cream and pipe the cream into the éclairs.
  25. Dip the top of each éclair into the chocolate glaze.
  26. Place on a wire rack until the glaze is set.