750 g (1 1/2 lb) potatoes, scrubbed and cut into chips
3 tablespoons olive oil
1/2 onion, sliced
1 teaspoon finely grated fresh root ginger
1 garlic clove, crushed
1/2 teaspoon ground coriander
1 tablespoon tomato purée
200 g (7 oz) cherry tomatoes
4 tablespoons white wine vinegar
2 tablespoons soft brown sugar
2 tablespoons low-fat mayonnaise
4 skinless cod loins, about 150 g (5 oz) each
75 g (3 oz) dried wholemeal breadcrumbs
finely grated rind of 1 lemon
salt and pepper
Cook the chips in boiling water for 3 minutes until just starting to soften. Drain and pat dry with kitchen paper. Toss with 2 tablespoons of the oil, season with salt and pepper and place on a large baking tray. Place in a preheated oven, 220°C (425°F), Gas Mark 7, for 25 minutes until golden and cooked through.
Meanwhile, heat the remaining oil in a saucepan. Add the onion and cook for 10 minutes until softened. Add the ginger, garlic, coriander and tomato purée and cook for a further 2 minutes. Add the tomatoes, vinegar, sugar and a splash of water. Leave to simmer for 10 minutes. Whizz in a small food processor or blender to form a chunky ketchup. Season and set aside.
While the ketchup is simmering, spread the mayonnaise all over the cod loins. Toss together the breadcrumbs and lemon rind. Dip the fish in the breadcrumbs until coated all over. Place on a baking sheet and cook in the oven, with the chips, for 12 minutes until just cooked through. Serve with the chips and ketchup.