To Make the Choux Pastry Dough:

Prepare the Ingredients: Measure all ingredients ahead of time. If filling with pastry cream, prepare it the day before. If filling with Chantilly cream, prepare it while the eclairs are baking.

Preheat Oven: Preheat your oven to 190°C (375°F) with fan, or 210°C (410°F) without fan. Line two half-sheet baking trays with parchment paper or silicone baking mats.

Heat Water and Butter: In a saucepan over medium heat, add the water, butter, sugar, and salt. Stir until the butter melts and the mixture starts to bubble around the edges.

Add the Flour: Once bubbles appear, turn off the heat and immediately add the flour. Stir continuously with a wooden spoon until the dough forms.

Cook the Dough: Turn the heat back on and cook the dough for 1 minute while stirring constantly. If using a stainless steel pot, you’ll notice a film of dough forming on the bottom.

Cool the Dough: Remove the saucepan from the heat and let the dough cool for about 10 minutes. Meanwhile, whisk the eggs together.

Incorporate the Eggs: Gradually add ¼ of the eggs to the cooled dough, mixing until fully combined. Continue adding the rest of the eggs in small increments, mixing after each addition until the dough is smooth and shiny. The dough should be stretchy but not too soft. If necessary, whisk an additional egg and add it a tablespoon at a time until the desired consistency is achieved.

To Pipe the Eclairs:

Prepare the Piping Bag: Fit a large piping bag with a 1.2cm (½-inch) French star tip or round tip.

Pipe the Dough: Pipe the dough into 10cm (4-inch) long eclairs on the prepared baking trays. Shape the ends of the eclairs slightly wider than the middle. Smooth the ends with a wet finger to prevent them from burning.

Dust with Powdered Sugar: Lightly dust the tops with powdered sugar to help them keep their shape and slightly sweeten them.

To Bake:

Bake the Eclairs: Bake in the center of the oven for 30-35 minutes until golden brown. Once done, open the oven door slightly, leaving a wooden spoon to hold it ajar, and let the eclairs rest for 5 minutes before removing them.

Cool: Transfer the eclairs to a cooling rack and let them cool completely.

To Decorate:

Prick the Bottoms: Use the end of a fork or knife to make two small holes in the bottom of each eclair.

Fill the Eclairs: Using a piping bag fitted with a small round tip, fill the eclairs through the holes with your filling of choice. They will become heavier as they’re filled.

To Glaze:

Prepare the Chocolate Glaze: Make the chocolate sauce while the eclairs bake.

Dip in Chocolate: Dip the top of each eclair into the chocolate sauce and gently shuffle it to ensure it’s evenly coated. Allow any excess glaze to drip off.

Serve:

Let the chocolate set before serving. Eclairs can be enjoyed chilled from the fridge or at room temperature.