Bring water to a boil. Wash and add zobo leaves to the water and steep for about 30 minutes to an hour.
Pour the Zobo juice through a sieve and Put the juice back into the pot and on to the heat. Add the sugar and on medium heat; while stirring occasionally, bring it to a slight boil until the mix starts showing visible thicker bubbles. Remove the syrup from the heat' let it cool a little; then add the vanilla and lemon juice if using and set aside for other uses.
Recipe by Nigerian Lazy Chef at https://www.nigerianlazychef.com/2015/07/zobo-syrup/