Preheat the oven to 350°F.

Prepare the pastry cream:

1. Mix together the egg yolks and sugar, then add the cornstarch and dilute completely. Add the coffee extract.

2. Heat the milk to a boil. Pour the boiling milk over the egg yolk mixture and whip vigorously to avoid lumps. Return this mixture to the saucepan and bring to a boil again. Set aside off the heat.

Prepare the puff pastry:

3. Bring to a boil the water, salt, and butter, then remove from the heat and add the flour little by little, mixing. Beat with a wooden spatula until a smooth, homogeneous dough is obtained.

4. Return to the heat and work the dough until it comes away from the sides of the saucepan. Remove from the heat again and incorporate the eggs one by one.

5. When the dough is ready, place it on a work surface and let it cool to lukewarm, folding it back onto itself from time to time with a spatula.

6. Fill a piping bag with a smooth tip with the puff pastry and form cream puffs 8 cm long.

7. Bake for 20/25 minutes or until golden brown. Let cool.

8. With the tip of a knife, pierce two holes spaced apart underneath each cooled cream puff. Fill with coffee cream through these holes.

9. Soften the coffee glaze and delicately dip the tops of the cream puffs. Even out with a spatula and finally decorate with lines of melted chocolate and shortbread cookies.