Mix together half of the harissa paste and ground cumin in a bowl. Rub the paste all over the ﬁsh ﬁllets and leave to marinate for 2 hours in the fridge.
Dust the ﬁllets with some ﬂour and shake off the excess. Heat olive oil in a wide frying pan over medium-high heat and fry the ﬁllets in batches for 2 minutes on each side.
Set ﬁsh aside, leave oil in the pan, and add onions. Stir as you cook for about 8 minutes until onions are golden.
Add remaining harissa, red wine vinegar, ground cinnamon, salt, and freshly ground black pepper. Pour in water, lower heat, and let sauce simmer gently for 5 to 10 minutes until quite thick.
Add the honey and rose water to the pan along with currants, if using, and simmer gently for a couple more minutes. Taste and adjust seasoning and then return ﬁsh ﬁllets to the pan. Spoon the sauce over the ﬁsh and leave them to warm up in the simmering sauce for 3 minutes. You may need to add a few tbsp of water if the sauce is very thick.
Serve warm or at room temperature, sprinkled with chopped cilantro, if using, and rose petals.
Recipe adapted from Jerusalem: A Cookbook by Yotam Ottolenghi and Sami Tamimi.