In the Mazandaran region of the Caspian Sea, where my inspiration for this recipe originated, the locals love to combine lots of fresh herbs with barberries.
In a mixing bowl, combine all the ingredients for the topping and toss well together. Set aside.
Line a rimmed sheet pan, or baking dish, with a layer of aluminum foil and a layer of parchment paper (allowing extra to overhang the edges of the sheet pan to help lift out the fish). Generously oil the parchment paper.