01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a medium saucepan, combine water, milk, butter, sugar, and salt. Bring to a boil over medium heat.
03 - Remove from heat and stir in the flour all at once. Return to heat and cook, stirring vigorously, until the dough forms a ball and pulls away from the sides (about 2 minutes).
04 - Transfer dough to a mixing bowl and let cool for 5 minutes. Beat in eggs one at a time, mixing well after each addition, until the dough is smooth and glossy.
05 - Spoon dough into 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.
06 - Bake for 20 minutes, then reduce oven temperature to 350°F and bake for another 15 minutes, or until golden and crisp. Cool completely on a wire rack.
07 - For the lemon cream, whisk together lemon juice, zest, sugar, and eggs in a heatproof bowl. Set over a simmering pot of water (double boiler) and whisk constantly until thickened (about 8 minutes).
08 - Remove from heat and whisk in butter until smooth. Chill until cold.
09 - Whip the heavy cream to stiff peaks, then gently fold into the chilled lemon curd to create a light mousse.
10 - Slice cooled éclairs in half horizontally. Pipe or spoon lemon cream onto the bottom halves. Add fresh raspberries, then cover with the top halves.
11 - For the glaze, whisk together powdered sugar, lemon juice, and zest until smooth and pourable. Spread or drizzle over the tops of the éclairs.
12 - Chill éclairs for at least 30 minutes before serving to allow the filling to set.