Preheat oven to 375 degrees F and prepare a baking sheet with aluminum foil and then spray with cooking spray.
Pat your fish fillets dry and season both sides with salt and pepper. Place fish on prepared sheet and drizzle with a little bit of olive oil.
Bake the fish for 12-15 minutes or until the internal temperature reaches 145 degrees F. Remove from the oven and allow to cool for 5-10 minutes.
Once the fish has cooled, shred the fish. In a bowl, combine the fish, panko breadcrumbs, mayonnaise, onion, 4 tsp lemon juice, half the parsley, and a pinch of pepper.
Warm up a frying pan over medium to low heat and add a drizzle of olive oil. Form the mixture into eight evenly-sized fish cakes. Cook the fish cakes in batches until browned just a couple of minutes on each side.
Serve the fish cakes with a garnish of parsley and a lemon wedge.