Heat water, butter, and salt until boiling, then stir in flour all at once until a smooth dough forms; cook for 1 minute.

Let the dough cool slightly, then mix in eggs one at a time until glossy; add a bit more egg if too stiff.

Preheat oven to 375°F and pipe 1-inch mounds onto a parchment-lined baking sheet; smooth peaks with a damp finger.

Bake 20–25 minutes until golden and firm, then cool fully on a rack.

Whip heavy cream, sugar, vanilla, and green food coloring until stiff peaks form.

Poke a hole in each puff and fill with the green cream using a piping bag.

Stack the filled puffs in a cone on a serving plate, using extra cream between layers for stability.

Finish with powdered sugar, sprinkles, and a star candy, then chill for 10 minutes to set.