Cream puff pastry:

1. Bring the milk to a boil.

2. In a bowl, whisk together the sugar, flour, and egg yolks until the mixture is pale. Pour in the hot milk and continue to mix with a whisk, without beating, until the mixture is smooth. Add the instant coffee and mix in. Transfer the mixture to a saucepan with a thick bottom. Heat over low heat, stirring constantly, until the mixture thickens.

3. Pour the mixture into a bowl and cover it with plastic wrap directly on the cream. Refrigerate.

Choux pastry:

4. Preheat the oven to 190C/375F.

5. Bring the water, salt, and butter to a boil.

6. Remove from heat and add the flour a little at a time, mixing. Stir vigorously with a wooden spatula until the dough is smooth and homogeneous. Return the dough to the heat and work it until it comes away from the sides of the pan. Remove from heat again and add the eggs one at a time. When the dough is ready, transfer it to your work surface and let it cool to lukewarm, folding it back onto itself from time to time with a spatula.

7. Fill a pastry bag with the choux pastry, fitted with a 1 cm diameter plain tip. Pipe batons of 8 to 10 cm in length onto a parchment-lined baking sheet.

8. Bake for about 30 minutes, or until they are golden brown. Let cool.

9. With the tip of a knife, make two holes spaced apart underneath each cooled éclair. Using a pastry bag fitted with a small tip, fill the éclairs with coffee cream through these holes.

10. Soften the glaze and gently glaze the top of the éclairs. Smooth out with a spatula or the back of a spoon.