Cod and spinach bake

1) Heat oven to 200C/180C fan/gas 6.
2) Fry the leeks and onions in the oil until they are soft and starting to caramelise, season to taste.
3) Meanwhile, put the spinach in a large dry frying pan over a medium heat and stir until just wilted.
4) Mix the breadcrumbs and cheese together.
5) Spread the onion and leek mixture on the bottom of an ovenproof dish large enough to take all of the cod in one layer.
6) Top with the cod, spinach and sundried tomato.
7) Season and sprinkle with cheese and breadcrumbs.
8) Bake in the oven for 15 - 20 mins, until golden.