For the topping: Boil plenty of water in a saucepan and add the sesame seeds. Boil for 3-4 minutes, then rinse off with plenty of cold water. Strain and spread on a towel. Add the aniseed and black cumin, mix well, and cover with the towel to keep moist.
For the dough: Pour ½ cup of lukewarm water into a bowl, add the yeast, mix, and set aside for 20 minutes to activate. In a large mixing bowl or the bowl of a mixer, combine both types of flour, anise, mastic, mechlepi, sugar, cinnamon, cloves, and salt. Mix together, then add the activated yeast and the rest of the water. Knead with a hook attachment for 5 minutes or by hand for 10 minutes until the dough forms a smooth ball. Place the dough in a bowl, score a cross on its surface, and cover with plastic wrap or a towel. Let it rise for about 1 hour.
After the dough has risen, knead it again and divide it into three parts to form 3 rings. Roll one piece into a large, thick stick about 30x5 cm. Coat it in the sesame seed mixture, ensuring the seeds adhere well. With a sharp knife, cut the dough vertically and slightly diagonally into 15 pieces, each about 2 cm. Leave the first piece on the left in place and join the rest by turning them from the opposite side, leaving the last part as is. Place the ring on a baking tray lined with non-stick greaseproof paper. Repeat with the remaining dough pieces.
Cover with a towel and let them rise for another hour. To test readiness, press the dough with your finger; if the imprint bounces back, it's ready to bake. Alternatively, place a small piece of dough in a cup of tap water; if it rises to the surface, the dough is ready. Bake in a preheated oven at 180°C with fan for 50 minutes.