In a medium saucepan, combine 1 cup of water and ½ cup of unsalted butter over medium heat until the butter melts. Stir in 1 cup of all-purpose flour and mix until a smooth ball forms, about 5 minutes. Remove from heat and cool for 10 minutes before adding 4 eggs one at a time.

Preheat the oven to 425°F (220°C) and line a baking sheet with parchment paper. Transfer choux pastry into a piping bag and pipe 4-inch long strips on the sheet, leaving space in between.

Bake for 25-30 minutes until puffed and golden brown. Avoid opening the oven door for the first 20 minutes.

In another saucepan over low heat, whisk together ½ cup lemon juice, 2 teaspoons lemon zest, ½ cup granulated sugar, and 1 egg until thickened, about 10 minutes. Fold in 1 cup whipped heavy cream.

For the raspberry glaze, combine 1 cup raspberries and ½ cup granulated sugar in a saucepan over medium heat. Cook for 5-7 minutes and strain through a sieve once the raspberries break down.

Once cooled, make a small slit in each eclair and pipe in the lemon cream. Dip the tops in raspberry glaze or drizzle it over the eclairs. Allow the glaze to set before serving.