I made the liqueur with freshly picked, dried and cracked ripe brown walnuts from the tree. Of course, you can also buy nuts that you have bought here.
Put all ingredients in a larger container and let it steep for 6 - 8 weeks in a dark place, e.g. in the storage room. Shake occasionally, especially at first!
After the ripening period, sieve and filter the liqueur. I always use two paper kitchen towels, as they are more stable than coffee filters, and place them in the funnel of the coffee machine.
The walnuts soaked with alcohol can still be used for other purposes, e.g., Mix with ice cream.