1) Prepare the Dijon caper mayonnaise by mixing all the ingredients together until smooth. Refrigerate until ready to use.
2) In a large bowl, mix together hake, 20g of bread crumbs, 15g parsley, mayonnaise, coriander, shallots, mustard, tuna and egg. Season with salt and pepper. Sprinkle remaining bread crumbs on a baking tray.
3) Form mixture into patties roughly 4-cm thick and 5-cm in diameter. Coat each fishcake with the bread crumbs and set aside.
4) Heat a large heavy saute pan over medium-high heat with enough vegetable oil to coat the bottom. Cook the fishcakes until browned on both sides, about 3 minutes per side, in batches as needed.