Whole milk- 1 1/2cup
Vanilla essence- 1 tsp
Egg yolks- 3
Sugar- 1/2 cup
Corn starch - 2tbs
Unsalted butter- 1 tbs
Water- 1 cup
8 tablespoons (1 stick) unsalted butter
Salt- 1/2 tsp
Sugar- 1 1/2 tsp
All purpose flour- 1 cup
Heavy cream- 1/2 cup
Dark chocolate- 4 ounce
To make the filling
In a medium saucepan, bring milk to a boil. Switch off the flame and let it cool down a bit. In a bowl, whisk the egg yolks and sugar until light and fluffy. Add the cornstarch and whisk vigorously until no lumps remain. Whisk in 1/4 cup of the hot milk and whisk until incorporated. Whisk in the remaining hot milk mixture, reserving the saucepan. Pour the mixture through a strainer back into the saucepan. Cook over medium-high heat, whisking constantly, until thickened and slowly boiling. Remove from the heat and stir in the butter. Let cool slightly. Cover with plastic wrap, lightly pressing the plastic against the surface to prevent a skin from forming. Chill at least 2 hours or until ready to serve.
To make the pastry
Preheat the oven to 350 degrees F. Line a sheet pan with parchment paper. If you wish you can mark a 6 or 7 template and set aside.
In a large saucepan, bring the water, butter, salt and sugar to a rolling boil over medium-high heat. When it boils, immediately take the pan off the heat. Stirring with a wooden spoon, add the flour and stir hard until all the flour is incorporated, and there is no lumps. Return to the heat and cook, stirring,continuously till it leaves the sides of the pan. It will be greasy to touch but should not stick to your hands. Scrape the mixture into a mixer fitted with a paddle attachment (or use a hand mixer). Mix at medium speed. With the mixer running, add 3 eggs, 1 egg at a time. Mix until the dough is smooth and glossy and the eggs are completely incorporated. The dough should be thick, but should fall slowly and steadily from the beaters when you lift them out of the bowl. If the dough is still clinging to the beaters, add the remaining 1 egg and mix until incorporated.
Using a pastry bag fitted with a large plain tip, pipe fat lengths of dough onto the lined baking sheet, leaving 2 inches of space between them. Use your fingers to smooth out any bumps of points of dough that remain on the surface. Bake 15 minutes, then reduce the heat to 325 degrees and bake until puffed up and light golden brown, about 25 minutes more.Let cool in the oven by keeping the over door ajar for 20 minutes
To pipe in the filling use a plain pastry tip. Cut one side open and pipe the custard filling or make a hole in the end of each eclair (or just use your fingertip). Using a pastry bag gently pipe the custard into the eclairs, using only just enough to fill the inside.
To make the glaze
In a small saucepan, heat the cream over medium heat just until it boils. Immediately turn off the heat. Put the chocolate in a medium bowl. Pour the hot cream over the chocolate and whisk until melted and smooth. Set aside and keep warm.
Dip the tops of the eclairs in the warm chocolate glaze and set on a sheet pan. Chill, uncovered, at least 1 hour to set the glaze. Serve chilled.