In a saucepan, over medium heat, drizzle the oil and add the onion, carrots, celery, garlic and leeks. Sauté for 2-3 minutes until translucent. add the smoked fish and diced fish. stir once. Then, Add the white wine and cream. Season well and bring to the boil. Simmer for 3-5 minutes until the fish turn opaque and flaky. Remove from the heat and transfer into the ceramic dish.
Next, prepare the toping. In a bowl, combine the bread crumb with the cornflakes, boiled egg, herbs if using and a drizzle of oil. Season well with salt and pepper.
Scatter the mixture over the fish and place immediately in the oven for 15-20 minutes until piping hot and crispy.
Remove from the oven and serve immediately with a side of crisp salad leaves!