Espresso Éclair Recipe

Prepare oven and piping equipment

Preheat the oven to 425°F (220°C). Fit a large pastry bag with a 1/2-inch round or long star tip (or use a plain tip). Line two baking sheets with parchment and draw 3-inch long spaced guide lines if desired.

Make the choux paste

In a medium saucepan combine 1 cup whole milk, 1/4 cup water, 4 tablespoons unsalted butter, 1 teaspoon granulated sugar and 1/4 teaspoon salt. Bring to a rolling simmer over medium heat so the butter melts and the mixture is just about to boil.

Add flour and cook

Remove pan from heat, add 3/4 cup all-purpose flour all at once and stir vigorously with a wooden spoon until a smooth dough forms. Return to medium-low heat and cook, stirring constantly, for about 1–2 minutes to dry the dough slightly (a thin film may form on the bottom).

Incorporate eggs

Transfer dough to a mixing bowl or the bowl of a stand mixer fitted with the paddle. Let cool 2–3 minutes (warm but not hot to avoid cooking the eggs). Beat in the 2 large eggs one at a time, mixing well after each addition until the dough is smooth and glossy and just holds a soft peak when lifted. If needed, add a teaspoon of beaten egg to adjust consistency; dough should be pipeable but not runny.

Pipe éclairs

Fill the prepared pastry bag and pipe 3–3½ inch long logs onto the lined baking sheets, spacing about 2 inches apart. Smooth any pointed tips with a wet fingertip. Beat the reserved 1 egg and brush a thin egg wash over each piped éclair.

Bake

Bake at 425°F (220°C) for 10 minutes, then reduce oven temperature to 375°F (190°C) without opening the door. Continue baking for 18–22 minutes until golden brown and puffed. Do not open the oven during this time to avoid collapse. If necessary, pierce each éclair with the tip of a knife to release steam and return to the oven for 2–3 minutes to dry the insides.

Cool

Remove éclairs to a wire rack and let cool completely before filling (about 30–45 minutes).

Warm dairy and dissolve espresso

In a small saucepan warm 1/2 cup whole milk and 1/2 cup heavy cream over medium heat until it just begins to steam (do not boil). Whisk in 2 teaspoons instant espresso powder until dissolved and remove from heat.

Whisk yolks and dry ingredients

In a medium bowl whisk together 3 egg yolks, 1/4 cup granulated sugar and 1.5 teaspoons cornstarch until pale and slightly thickened.

Temper and thicken

Slowly pour about one-quarter of the hot milk-espresso mixture into the yolk mixture while whisking constantly to temper. Then pour the tempered yolk mixture back into the saucepan with the remaining hot milk, return to medium-low heat and cook, whisking constantly, until the mixture thickens to a custard that coats the back of a spoon (about 3–5 minutes). Do not boil vigorously to avoid curdling.

Finish crèmeux

Remove from heat and whisk in 2 tablespoons cold diced unsalted butter and 1/2 teaspoon vanilla extract until smooth and shiny. If texture is slightly grainy, pass the mixture through a fine-mesh sieve. Transfer to a bowl, cover surface with plastic wrap to prevent a skin, and chill until fully cold (at least 2 hours). Chilled crèmeux will thicken to a pipeable consistency.

Make glaze

Place 3 ounces chopped semisweet chocolate in a heatproof bowl. Warm 1 teaspoon light corn syrup and 1 teaspoon unsalted butter in a very small saucepan or microwave until just melted. Pour over chocolate and let sit 30 seconds, then stir until smooth. Allow glaze to cool slightly so it is pourable but not watery.

Glaze éclairs

Dip the top of each filled éclair into the glaze, or spread glaze over the top with a small spatula. Let glaze set for a few minutes before serving.

Fill éclairs

Transfer chilled espresso crèmeux to a pastry bag fitted with a small round tip (about 1/8–1/4 inch). Either: (a) slice each éclair horizontally and pipe crèmeux onto the bottom half then replace the top; or (b) poke three small holes along the bottom of each éclair and pipe crèmeux into the center until slightly plump. Use about 2–3 tablespoons crèmeux per éclair depending on size.

Glaze and dust

If using glaze, finish tops as described in the Chocolate Glaze section. Optionally dust a light pinch (about 1/4 tsp distributed across the batch) of espresso powder over the glazed tops for extra coffee aroma.

Chill and serve

Chill assembled éclairs for at least 30 minutes to let the filling set and glaze firm slightly. Serve within 24 hours for best texture; store refrigerated in a covered container for up to 2 days.