Elderflower-cured mackerel with tomato consommé

To make the tomato consommé, put all the ingredients into a bowl with 1 tsp salt and ½ tsp cracked black pepper. Cover, and leave the to macerate for 24 hours at room temperature.

The next day, line a sieve with a piece of clean muslin or J-cloth, and put over a large bowl. Pour the macerated mixture into the sieve and leave to drain for an hour, until all the liquid has drained from the tomatoes. Discard the solids, and keep the clear consommé.

Lightly season the mackerel with a pinch of rock salt. Mix the pickle ingredients and pour over the mackerel in a shallow dish. Leave for 30 minutes to cure the mackerel. Drain the mackerel of pickling liquid, drizzle with a little olive oil and cut into thick slices.

Blanch the basil in pan of boiling water for 1 minute. Drain, and refresh in ice water, then drain again. Put the cooked leaves into a small blender and blitz with the oil. Strain the oil through another piece of clean muslin or J-cloth, and collect the green oil that remains. This will last in the fridge for up to a week.

Cover the dried seaweed in cold water and leave to soak until it doubles in size, about 10 minutes. Pat dry with kitchen paper.

Add the whole heirloom tomatoes to boiling water for 15 seconds. Then quickly remove and refresh in ice water. Peel the skins off. Cut the tomatoes into quarters if large.

To serve, divide the heirloom tomatoes among 4 plates. Add the seaweed, cured mackerel and nasturtium leaves, if using. Drizzle over the basil oil, and serve with a jug of the tomato consommé to pour over at the table.