Preheat your oven to 400°F and line a baking sheet with parchment paper.

In a medium saucepan, combine water and butter, bringing it to a boil over medium heat.

Once boiling, remove from heat and stir in flour and salt until the mixture forms a ball. Let it cool for about 5 minutes.

Add eggs one at a time, mixing well after each addition until the dough is smooth and glossy. Stir in vanilla extract.

Transfer the dough to a piping bag fitted with a large round tip and pipe 4-inch long strips onto the prepared baking sheet, leaving space between each.

Bake for 25-30 minutes, or until golden brown and puffed. Turn off the oven and let the eclairs cool inside for 10 minutes with the door slightly ajar.

Remove from the oven and let cool completely on a wire rack.

While the eclairs cool, prepare the filling by whipping the heavy cream, powdered sugar, instant coffee granules, and vanilla extract until stiff peaks form.

Once the eclairs are cool, make a small slit in the side of each eclair and fill with the coffee cream filling using a piping bag.

For the chocolate glaze, heat the chopped chocolate, heavy cream, and butter in a small saucepan over low heat, stirring until smooth. Remove from heat and let cool slightly.

Dip the top of each filled eclair into the chocolate glaze, allowing excess to drip off, and place on a wire rack to set.

Serve immediately or refrigerate until ready to serve.