Chocolate-Coffee Paris-Brest Eclairs

For the Choux Pastry

1. Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper. In a medium saucepan, combine water, butter, sugar, and salt. Bring to a rolling boil over medium heat.
2. Remove from heat and immediately add the sifted flour, stirring vigorously with a wooden spoon until a smooth ball of dough forms and pulls away from the sides of the pan.
3. Transfer the dough to a large mixing bowl. Beat in the eggs one at a time, ensuring each egg is fully incorporated before adding the next. The dough should be smooth and glossy. Transfer the choux pastry to a piping bag fitted with a large star tip.
4. Pipe 6-inch long eclair shapes onto the prepared baking sheet, leaving about 2 inches between them. Bake for 20 minutes, then reduce the oven temperature to 350°F (175°C) and bake for another 10-15 minutes, until golden brown and firm. Turn off the oven, prop the door open slightly, and let the eclairs cool in the oven for 15 minutes to prevent them from deflating. Transfer to a wire rack to cool completely.

For the Chocolate-Coffee Cream Filling

1. Place the chopped dark chocolate in a heatproof bowl. In a small saucepan, heat 1 cup of heavy cream with the espresso powder until it just begins to simmer. Pour the hot cream over the chocolate and let it sit for 5 minutes, then whisk until smooth. Let cool completely, then refrigerate for at least 30 minutes, or until well chilled.
2. In a separate cold bowl, whip the remaining 1 cup of heavy cream with the powdered sugar and vanilla extract until medium-stiff peaks form.
3. Gently fold the whipped cream into the chilled chocolate-espresso mixture until just combined. Transfer the filling to a piping bag fitted with a small round tip.

For the Chocolate Glaze

1. Place the chopped dark chocolate in a heatproof bowl. In a small saucepan, heat the heavy cream and corn syrup until it just begins to simmer.
2. Pour the hot cream mixture over the chocolate and let sit for 5 minutes, then whisk until smooth. Whisk in the cocoa powder until fully incorporated and the glaze is glossy. Let cool slightly until it thickens to a pourable consistency.

Assembly

1. Once the choux pastry shells are completely cool, make three small holes in the bottom of each eclair with a small knife or piping tip. Pipe the chocolate-coffee cream filling into each eclair until it feels full.
2. Dip the top of each filled eclair into the prepared chocolate glaze, allowing any excess to drip off. Place on a wire rack and refrigerate for at least 30 minutes for the glaze to set.
3. Serve chilled and enjoy your elegant Chocolate-Coffee Paris-Brest Eclairs!