6 tablespoons unsalted butter (3/4 stick), cut into 6 pieces
1/4 cup plus 2 tablespoons whole milk
1/4 cup plus 2 tablespoons water, plus more as needed
1 tablespoon granulated sugar
1/4 teaspoon fine salt
3/4 cup all-purpose flour
3 large eggs, at room temperature
For the filling:
1/2 cup cold heavy cream
1/2 cup cold mascarpone cheese (about 4 ounces)
2 tablespoons sweet Marsala wine (or Kahlua)
2 tablespoons powdered sugar
1/2 teaspoon vanilla extract
For the glaze:
2 tablespoons heavy cream, plus more as needed
2 tablespoons sweet Marsala wine (or Kahlua)
1 teaspoon instant espresso powder
1 cup powdered sugar, sifted
1 tablespoon Dutch-process or unsweetened natural cocoa powder
Heat the oven to 220°C (425°F) and arrange a rack in the middle. Line a baking sheet with parchment paper; set aside.
Heat the butter, milk, measured water, sugar, and salt in a medium heavy-bottomed saucepan over medium-high heat until the butter has melted and the liquid has come to a boil. Reduce the heat to low, add the flour all at once, and stir vigorously with a wooden spoon until well incorporated.
Cook, stirring constantly, until the dough looks shiny and feels smooth to the touch, and a thin film has formed on the bottom of the pan, about 5 minutes. (The dough will easily form 1 large ball.)
Transfer the dough to the bowl of a stand mixer fitted with a paddle attachment and let it cool for 5 minutes. Meanwhile, fill a small bowl with water and set it aside.
With the mixer on medium-low speed, add 1 of the eggs and beat until completely incorporated, at least 1 minute. Add the second egg and beat until completely incorporated, at least 1 minute. Stop the mixer and scrape down the beater and the sides of the bowl with a rubber spatula. Return the mixer to medium-low speed, add the remaining egg, and beat until the mixture is smooth, sticky, and glossy, at least 1 minute more.
Transfer the dough to a large piping bag fitted with a 1/2-inch round tip. (Alternatively, place the dough in a large resealable plastic bag and cut off about 1/2 inch from one bottom corner.) Pipe 20 (2-1/2-by-1-inch) fingers onto the prepared baking sheet, making sure they’re about 1 inch apart.
Gently pat down any wispy tips with a finger dipped in the reserved bowl of water.
Place the baking sheet in the oven, reduce the temperature to 350°F, and bake until the puffs are golden brown, airy, and completely dry inside, about 30 to 35 minutes (do not open the oven door until at least 30 minutes has passed). Transfer the baking sheet to a wire rack and let the puffs cool completely, at least 20 minutes.
For the filling:
When ready to serve, place all of the filling ingredients in the bowl of a stand mixer fitted with a whisk attachment. Whisk on low speed until the powdered sugar is just incorporated. Increase the speed to high and whisk until medium peaks form, about 30 seconds more.
Transfer the mixture to a large piping bag fitted with a 1/2-inch round tip. (Alternatively, place the filling in a large resealable plastic bag and cut off about 1/2 inch from one bottom corner.) Place in the refrigerator while you make the glaze.
For the glaze:
Whisk the cream, Marsala, and espresso powder together in a medium bowl until smooth. Add the powdered sugar and whisk until smooth; set aside. (If the mixture is too thick to easily run off a spoon, whisk in more cream 1/2 teaspoon at a time.)
Using a paring knife, cut a slit in the long side of each éclair, being careful not to cut all the way through the pastry. Gently open up the éclairs.
Remove the filling from the refrigerator and pipe it into the bottom half of each éclair.
Close the éclairs. Carefully pick them up with your fingers, dip the tops in the glaze, then return them to the baking sheet glaze-side up.
Place the cocoa powder in a fine-mesh strainer and sift it generously over the tops of the éclairs. Let sit until the glaze sets, about 30 minutes.
In a heavy bottomed medium saucepan, bring the milk, water, butter, sugar and salt to the boil.
Once the mixture is at a rolling boil, add all of the flour at once, reduce the heat to medium and start to stir the mixture vigorously with a wooden spoon. The dough comes together very quickly. Do not worry if a slight crust forms at the bottom of the pan, it’s supposed to. You need to carry on stirring for a further 2-3 minutes to dry the dough. After this time the dough will be very soft and smooth.
Transfer the dough into a bowl of a mixer fitted with the paddle attachment, or using your handmixer or if you still have the energy, continue by hand. Add the eggs one at a time, beating after each egg has been added to incorporate it into the dough. You will notice that after you have added the first egg, the dough will separate, once again do not worry. As you keep working the dough, it will come back all together again by the time you have added the third egg. In the end the dough should be thick and shiny and when lifted it should fall back into the bowl in a ribbon.
The dough should be still warm. It is now ready to be used for the éclairs as directed below.
Once the dough is made you need to shape it immediately.
You can pipe the dough and the freeze it. Simply pipe the dough onto parchment-lined baking sheets and slide the sheets into the freezer. Once the dough is completely frozen, transfer the piped shapes into freezer bags. They can be kept in the freezer for up to a month.
Preparing the Éclairs
Cream Puff Dough (see above for recipe), fresh and still warm
Preheat your oven to 200 ºC (395 ºF). Divide the oven into thirds by positioning the racks in the upper and lower half of the oven. Line two baking sheets with waxed or parchment paper.
Fill a large pastry bag fitted with a 2/3 (2cm) plain tip nozzle with the warm cream puff dough. Pipe the dough onto the baking sheets in long, 4 to 41/2 inches (about 11 cm) chubby fingers. Leave about 2 inches (5 cm) space in between each dough strip to allow them room to puff. The dough should give you enough to pipe 20-24 éclairs.
Slide both the baking sheets into the oven and bake for 7 minutes. After the 7 minutes, slip the handle of a wooden spoon into the door to keep in ajar. When the éclairs have been in the oven for a total of 12 minutes, rotate the sheets top to bottom and front to back. Continue baking for a further 8 minutes or until the éclairs are puffed, golden and firm. The total baking time should be approximately 20 minutes.
The éclairs can be kept in a cool, dry place for several hours before filling.
Chocolate Pastry Cream
2 cups (500g) whole milk
4 large egg yolks
6 tbsp (75g) sugar
3 tablespoons cornstarch, sifted
7 oz (200g) bittersweet chocolate, melted
2½ tbsp (1¼ oz: 40g) unsalted butter, at room temperature
In a small saucepan, bring the milk to a boil. In the meantime, combine the yolks, sugar and cornstarch together and whisk in a heavy-bottomed saucepan.
Once the milk has reached a boil, temper the yolks by whisking a couple spoonfuls of the hot milk into the yolk mixture. Continue whisking and slowly pour the rest of the milk into the tempered yolk mixture.
Strain the mixture back into the saucepan to remove any egg that may have scrambled. Place the pan over medium heat and whisk vigorously (without stop) until the mixture returns to a boil. Keep whisking vigorously for 1 to 2 more minutes (still over medium heat).Stir in the melted chocolate and then remove the pan from the heat.
Scrape the pastry cream into a small bowl and set it in an ice-water bath to stop the cooking process. Make sure to continue stirring the mixture at this point so that it remains smooth.
Once the cream has reached a temperature of 140 F remove from the ice‐water bath and stir in the butter in three or four instalments. Return the cream to the ice‐water bath to continue cooling, stirring occasionally, until it has completely cooled. The cream is now ready to use or store in the fridge.
The pastry cream can be made 2‐3 days in advance and stored in the refrigerator.
In order to avoid a skin forming on the pastry cream, cover with plastic wrap pressed onto the cream.
Tempering the eggs raises the temperature of the eggs slowly so that they do not scramble.
1/3 cup (80g) heavy cream
3½ oz (100g) bittersweet chocolate, finely chopped
4 tsp (20 g) unsalted butter, cut into 4 pieces, at room temperature
7 tbsp (110 g) Chocolate Sauce (recipe below), warm or at room temperature
In a small saucepan, bring the heavy cream to a boil. Remove from the heat and slowly begin to add the chocolate, stirring with a wooden spoon or spatula.
Stirring gently, stir in the butter, piece by piece followed by the chocolate sauce.
If the chocolate glaze is too cool (i.e. not liquid enough) you may heat it briefly in the microwave or over a double boiler. A double boiler is basically a bowl sitting over (not touching) simmering water.
It is best to glaze the eclairs after the glaze is made, but if you are pressed for time, you can make the glaze a couple days ahead of time, store it in the fridge and bring it up to the proper temperature (95 to 104 F) when ready to glaze.
4½ oz (130 g) bittersweet chocolate, finely chopped
1 cup (250 g) water
½ cup (125 g) crème fraîche, or heavy cream
1/3 cup (70 g) sugar
Place all the ingredients into a heavy‐bottomed saucepan and bring to a boil, making sure to stir constantly. Then reduce the heat to low and continue stirring with a wooden spoon until the sauce thickens.
It may take 10‐15 minutes for the sauce to thicken, but you will know when it is done when it coats the back of your spoon.
You can make this sauce ahead of time and store it in the refrigerator for two weeks. Reheat the sauce in a microwave oven or a double boiler before using.
This sauce is also great for cakes, ice-cream and tarts.
ASSEMBLING THE ÉCLAIRS:
Chocolate glaze (see below for recipe)
Chocolate pastry cream (see below for recipe)
Slice the éclairs horizontally, using a serrated knife and a gently sawing motion. Set aside the bottoms and place the tops on a rack over a piece of parchment paper.
The glaze should be barely warm to the touch (between 95 – 104 ºF or 35 – 40 ºC, as measured on an instant read thermometer). Spread the glaze over the tops of the éclairs using a metal icing spatula. Allow the tops to set and in the meantime fill the bottoms with the pastry cream.
Pipe or spoon the pastry cream into the bottoms of the éclairs. Make sure you fill the bottoms with enough cream to mound above the pastry. Place the glazed tops onto the pastry cream and wriggle gently to settle them.
If you have chilled your chocolate glaze, reheat by placing it in a bowl over simmering water, stirring it gently with a wooden spoon. Do not stir too vigorously as you do not want to create bubbles.
The éclairs should be served as soon as they have been filled.