Nathen Outlaw cooks steamed bass and tomatoes with sardine and tomato ketchup on Saturday Kitchen live.

Nathen says: “Try making your own sardine-flavoured ketchup for this delicate steamed fish and tomato dinner for two.”

The ingredients are: dash olive oil, 2 red onions, 2 garlic cloves, 1kg/2lb 4oz ripe tomatoes,75g caster sugar, 2 bay leaves, 1 rosemary sprig, leaves only, 200ml red wine vinegar, 2 x 120g tins good-quality sardines in tomato sauce, 2 ripe plum tomatoes, 1 garlic clove, chopped, 1 rosemary sprig, leaves only, 1 tsp caster sugar, sea salt and freshly ground black pepper, 2 bass fillets, about 200g/7oz each, pin-boned and large handful of rocket leaves, to serve.