Preheat the oven to 180C/350F/Gas Mark 4.
To prepare the crust for the fish, melt 100g of butter in a saucepan and stir in the breadcrumbs, grated lemon zest, Parmesan cheese, chopped herbs and seasoning. Combine all the ingredients then remove from the heat and allow to cool for a couple of minutes.
Place the portions of fish on a roasting tray. Spread some O’Hellmann’s on the fish and top with the breadcrumb mixture. Press mixture onto the top of the fish.
Bake in the oven for 20 minutes until the topping has become nice and crunchy.
In the meantime, cover the potatoes with water and add garlic cloves.
Bring to a boil and simmer for 15-20 minutes until cooked then strain to remove the excess water. Place the potatoes through a potato ricer to remove any lumps; then add the cream, butter, spring onions and season with salt and pepper. Keep warm until required.
Serve in a shallow dish. Pipe on some mashed potato, place the fish on top and add the cherry tomatoes around. Some fresh herbs can be added on top of the fish.