Soak the isinglass in cold water. Assemble the egg yolks with the sugar and a pinch of salt until you get a very light and fluffy mixture. Join the Porto and mix with a whisk. Transfer the mixture into a steel container and cook in a bain-marie for about 10 minutes, mix often with the whisk, until it is swollen and firm. Drain the isinglass from the water, squeeze it well and add it to zabaione and contemporarily mix.
Cool the zabaione in Freddy with the blast chilling for about 15 minutes, then add the Greek yogurt and mix well so as to mix all the ingredients.
Pour the mixture in a plumcake mould, or in convenient silicone muffin monoportions, and freeze with Freddy’s shock freezing function for about 1 hour and 45 minutes. Remove the semi-cold from the loaf mould, dipping it quickly in hot water, or moulds from muffins, and serve with the melon thinly sliced and a sprinkling of poppy seeds.