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

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

Once boiling, remove from heat and stir in flour and salt until the mixture forms a ball.

Let the mixture 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.

Pipe 4-inch long strips onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 20-25 minutes, or until the eclairs are puffed and golden brown. Do not open the oven door during baking.

Once done, remove from the oven and let cool completely on a wire rack.

While the eclairs cool, prepare the chocolate glaze by heating the heavy cream until it just begins to simmer.

Remove from heat and add the chocolate chips. Let sit for 2 minutes, then stir until smooth.

Once the eclairs are cool, slice them in half lengthwise.

Fill the bottom half with whipped cream or pastry cream, then dip the top half into the chocolate glaze.

Place the top back on the filled eclair.