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

In a medium saucepan, combine water and butter over medium heat until melted and boiling. Remove from heat.

Add flour and salt all at once, stirring vigorously until a ball forms and pulls away from the pan. Let cool for 5 minutes.

Add eggs one at a time, mixing well after each until smooth and glossy. Stir in vanilla extract.

Scoop or pipe dough onto the baking sheet in small mounds, about 2 inches apart. Bake for 20-25 minutes until golden brown and puffed. Do not open the oven door during baking.

Remove from oven and let cool completely on a wire rack.

While cooling, prepare the lemon cream filling by whipping heavy cream until soft peaks form. Gradually add powdered sugar, lemon zest, lemon juice, and vanilla extract, whipping until stiff peaks form.

Once pastries are cool, slice in half or poke a hole in the bottom. Fill each pastry with lemon cream using a piping bag or spoon.

Serve immediately or refrigerate until ready to serve.