Prepare Dough: In a medium saucepan, combine the butter, water, and salt. Bring to a boil over medium heat. Add the flour all at once and stir vigorously until the mixture forms a ball and pulls away from the sides of the pan.
Add Eggs: Remove from heat and let the mixture cool slightly. Add the eggs one at a time, beating well after each addition until the dough is smooth and shiny.
Pipe or Scoop Dough: Transfer the dough to a piping bag fitted with a large round tip, or use a spoon to drop rounded tablespoonfuls onto the prepared baking sheet, spacing them about 2 inches apart.
Bake: Bake for 15 minutes, then reduce the oven temperature to 375°F (190°C) and bake for an additional 20-25 minutes, or until the puffs are golden brown and crisp. Turn off the oven and let the puffs cool inside the oven with the door slightly open.
Make the Mascarpone Filling:
Whip Ingredients: In a mixing bowl, combine the mascarpone cheese, heavy cream, powdered sugar, vanilla extract, lemon zest, and lemon juice. Beat until smooth and thickened.
Chill: Refrigerate the filling until ready to use.
Assemble the Cream Puffs:
Cut Puffs: Once the cream puffs are completely cool, use a sharp knife to cut them in half horizontally.
Fill Puffs: Spoon or pipe the mascarpone filling into the bottom halves of the cream puffs, then replace the top halves.
Optional Lemon Glaze:
Mix Glaze: In a small bowl, whisk together the powdered sugar and lemon juice until smooth. Adjust the consistency by adding more lemon juice if needed.
Drizzle: Drizzle the glaze over the filled cream puffs.
Serve:
Enjoy!
