**Make the Choux Pastry:**,1. Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.,2. In a medium saucepan, combine water, butter, and salt. Bring to a boil.,3. Remove from heat, add flour all at once, and stir vigorously.,4. Return to heat and cook for 1–2 minutes, stirring constantly, until dough pulls away from sides.,5. Cool for 5 minutes. Beat in eggs one at a time until dough is smooth and glossy.,6. Pipe or spoon small mounds onto prepared baking sheet.,7. Bake for 20–25 minutes, until puffed and golden. Turn off oven, crack door, and let cool for 10 minutes. Transfer to a wire rack.,**Make the Lemon Cream Filling:**,1. In a saucepan, whisk lemon juice, zest, sugar, cornstarch, and egg yolks.,2. Cook over medium heat, stirring constantly, until thickened (about 5–7 minutes).,3. Remove from heat and stir in butter. Cool completely.,4. Whip cream to stiff peaks. Fold into cooled lemon curd to make mousse-like filling.,**Assemble Cream Puffs:**,1. Slice puffs in half or poke a hole in the bottom.,2. Pipe or spoon in lemon cream.,3. Dust with powdered sugar or glaze before serving.