Rinse your Tulsi leafs before cooking so to get rid of all impurities. Grab a pot, add all the 350 milliliter Water and the leafs and let it cook on a slow flame until the first boil. Remove from the heat and cover. Let the Tulsi leafs sit in the Water for 20 minutes at least.
Strain the liquid and press out all the juice from the leafs. Discard the leafs and add the Tulsi flavored Liquid back into the pot together with the 120 grams Sugar.
Keep on a low flame and mix until the sugar is all dissolved. Then keep for another few minutes on the heat until the first boil appears. Close the heat and just let the sugary syrup sit until it has cooled down. Strain if necessary again to get rid of any impurities.
Grab a sterilized bottle and fill with the syrup. Seal well and store in a cool and dry place. Can be kept for a few months if stored in the fridge.