Chop the aubergine, courgette and peppers into a 1cm dice.
Finely slice your onions and mince your garlic.
Add the aubergine, courgette, peppers and onions into a hot frying pan with vegetable oil and season with salt and pepper. Cook for 5 minutes.
Add your minced garlic and cook for a further minute.
Then transfer the vegetables into a saucepan and add the chopped tomatoes, mixed herbs and a splash of hot water.
Bring to the boil and simmer for 5 minutes.
In the meantime, slice your bread and toast.
Season the ratatouille with balsamic vinegar, sugar, salt and pepper.
Turn the heat down low and place a steamer tray on top of the saucepan. Place a layer of parchment paper down.
Coat the fish in a touch of oil and season with salt. Place into the steamer and top with a lid. Steam for 2 minutes or until it is cooked.
Plate with a generous amount of ratatouille on the bottom. Place the fish on top and grate some lemon zest on top. Garnish with some fresh basil leaves and serve with some toasted baguette.
Enjoy!