For 4 people
Take the green walnuts and cut them into quarters. Then, infuse them in brandy for 60 days in a container away from heat and humidity.
After that, filter out the green walnut pieces and keep the brandy.
In a large saucepan, combine powdered sugar and water to make a smooth, glossy syrup.
Let the syrup cool and filter it through a sieve.
Then mix the syrup, the green walnut pieces and the reserved brandy in a large bottle and close it tightly.
Let the green walnut liqueur age for 3 months in a cool, dry place away from light before enjoying it in moderation as an aperitif.