Agar is a vegetarian gelling agent derived from dried seaweed. Although some agar is wild harvested, it is more commonly farmed commercially.
Like gelatine, agar is thermo-reversible but at much higher temperatures, and it has around 5 times the setting properties – so much less is needed. Unlike gelatine, agar sets at room temperature but will hold its shape when hot.
Heat the carrot juice and add the gellan, bring to the boil, whisking to incorporate the gellan. Pour into a mould and leave to set.
Melt the Parmesan cheese in a hot non-stick frying pan, remove and cut into strips. Leave to cool until they are crispy.
Salt the mackerel fillets, leave for 10 minutes then rinse and dry.
Heat the white wine vinegar, add the spices and sugar, bring to the boil then leave to cool. Strain and pour into a plastic container. Add the mackerel fillets and leave to pickle for 20 minutes.
Bring the beetroot juice to the boil, season with salt then add the gellan. Pour into moulds and leave to set.
Serve with thinly sliced goat’s cheese and watercress.
Cut the rhubarb into 3-4cm lengths and heat the butter and sugar together in a saucepan until it begins to foam. Add the rhubarb and cook for 2 minutes, turning halfway through. Add the orange juice and allow the rhubarb to cook until just tender. Remove from the pan and reduce the remaining liquid to a glaze.