Slice one lemon into slim slices to top the fish. From the other lemon, grate off the zest and set aside the zested lemon and slices.
Stir the oil, olives, pesto and lemon zest together in a small bowl.
Drape the fish pieces in an oven proof dish and top each piece with the pesto mixture. Sprinkle over breadcrumbs, parmesan and a couple of lemon slices.
Season with salt and pepper and bake for 15 minutes until fish is cooked. Squeeze some juice from the remaining lemon over the top to serve.
Notes
You may substitute haddock with other white fish such as cod or basa.