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

Let dough cool slightly, then mix in eggs one at a time until glossy and smooth; add a little extra egg if too stiff.

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

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

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

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

Stack puffs in a cone shape, using extra cream between layers for stability.

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