Pre-heat oven to 200°C/gas mark 6, line a baking tray and grease lightly with oil
Place the crab meat, breadcrumbs, lemon zest and juice, 2tbsp olive oil, chives, parsley and tarragon leaves into a large bowl, stir to combine and season
Place the cod portions onto the baking tray and divide the crab mix evenly over the top, press the mixture down gently and drizzle over the remaining oil, place into the oven for 15-20 minutes until the fish is cooked through