For the fennel-anise jam, boil fennel with water, anise, salt and lemon juice for 10-15 minutes until soft, mix if necessary.
Stir in jelling sugar and boil until simmering, about 4-5 minutes. Make a jelly test.
Stir in aniseed schnapps and pour into prepared glasses.
With the help of an eyedropper, drizzle a few drops of alcohol over the top, light and seal immediately.