1 tbsp chopped fresh basil
2 garlic cloves, finely chopped
12 new potatoes, diced and boiled
2 onions, sliced
2 handfuls baby spinach leaves
125ml/4fl oz vegetable or fish stock
2 x 400g/14oz cans of chopped tomatoes
salt and freshly ground black pepper
1 tbsp olive oil
4 x 200g/7oz firm white fish fillets