Clean, wash and cut the rhubarb into small pieces. Simmer covered with 1/2 litre water, cinnamon sticks and anise stars for about 30 minutes. Then drain on a sieve lined with a gauze cloth for at least 30 minutes.
Measure out 3/4 litre juice. Fill up with water if necessary. Mix juice and jam sugar in a large pot, bring to the boil while stirring and boil for 4 minutes until bubbly. Pour hot into carefully prepared glasses.
Decorate as you like with cinnamon sticks and star anise. The jelly can be filled into nice glasses and sealed tightly with cellophane. Otherwise fill into prepared twist-off jars, close them tightly and put them upside down for about 5 minutes.
Turn around again. Store in a cool and dark place. Results in about 4 glasses (from 200-300 ml content).