When a sweet, classic French treat meets an equally iconic Italian dessert, yumminess ensues.
1 cup water
1/2 cu (1 stick) unsalted margarine, cut in to small pieces
1 teaspoon sugar
1/2 teaspoon salt
220 grams all-purpose flour
4 eggs + 1 egg white
250 milliliters of skim milk
3 egg yolks
50 grams sugar
1 tablespoon flour
1 tablespoon cornstarch
50 grams 185 grams butter + butter
2 teaspoons instant coffee powder
400 milliliters thickened / whipping cream (at least 35 percent fat content)
3-4 tablespoons mascarpone cheese
1 teaspoon vanilla bean paste
Cocoa powder to dust
Place milk and coffee powder into a large microwave safe bowl and microwave for 1 min. Stir to combine and dissolve coffee powder. Set aside.
In a large mixing bowl, mix the yolks, vanilla bean paste and the sugar and whisk until well combined and the mixture lightens in color. Add the corn flour and plain flour and stir until mixture is smooth Add 1/3 of the hot milk and stir well. Then slowly add the rest of the milk while stirring
Transfer to a medium sized saucepan and stir on medium heat until mixture thickens and becomes smooth. You should be able to run your finger along the back of the spoon and it will be thick enough to not come back together.
Add the cold butter cubes and stir until well combined.
Transfer custard to a bowl, cover with plastic wrap and refrigerate for at least 3-4 hours or overnight to allow it to completely set. Whip up again right before you're ready to frost to get it to a nice smooth consistency.
To make thin custard filling, microwave for 1 min, take about 1 cup of custard and add 175 milliliters warm milk to it. Stir until well combined.
Bring the water, margarine, sugar and salt to a boil in a medium saucepan. Remove the pan from the heat and quickly stir in the flour with a wooden spoon.
Cook the mixture over medium-high heat, stirring constantly with the wooden spoon, until the mixture pulls away from the sides of the pan and film forms on the bottom of the pan, around 1-2 minutes.
Transfer the dough to a stand mixer and mix on low with the paddle attachment until slightly cooled, around 1 minute. Raise the speed to medium and add each egg, 1 at a time, until soft peaks form in the batter with touched with your finger. This should take around 5 minutes.
Preheat the oven to 220C (425F) and prepare two baking sheets with parchment paper. Fill a pastry bag with the batter and pipe out donut shapes, around 4 centimeters in wide. Brush with egg wash (1 egg whisked with 2 tablespoons milk)
Place the unbaked éclairs in the oven for 10 minutes, reduce the oven temperature to 350 degrees F and bake until golden brown, for 25 more minutes. Take out the baked pastries and placed them on a wire rack to cool.
To prepare mascarpone cream, add whipped cream and vanilla to a large mixing bowl. Whip to soft peaks using a hand mixer. Add mascarpone cheese and whip to stiff peaks.
Poke three holes on the top of each éclair. Fill a piping bag with the coffee pastry cream and fill each éclair. Drizzle with chocolate sauce and allow it to set for 10 min.
Fit the end of a piping bag with a small round tip and fill with mascarpone cream. Pipe little blobs in a row. Finish off a with a dusting of cocoa powder.