Heat the milk with the seeds from the vanilla pod.
In a bowl, whisk the yolks and whole eggs with the sugar until the mixture whitens.
Add the corn starch.
Pour the hot milk over the mixture and whisk.
Return to saucepan and whisk. Cook on low heat – the cream should thicken. The whisk should clean spaces at the bottom of the pan. Share out the cream into three portions and flavour with the desired fragrance: rose, violet, and pistachio. - for rose and violet: a few drops of extract is enough - for the pistachio: mix the pistachio paste with the cream and whip vigorously.
Cool in the refrigerator covered with Clingfilm that is in contact with the cream to avoid the formation of a thin layer of dry cream.
Add the whipped cream to each flavoured cream.
Preheat oven to 220°C.
Heat the water, sugar, and salt in a saucepan and add the butter in pieces.
Bring the mixture to the boil and remove the saucepan from the heat.
Add the flour and mix vigorously with a spoon. Return the saucepan to the heat. Continue to mix until the dough dries and no longer sticks to the saucepan.
Put the dough in a large bowl and fold in the eggs one by one until you obtain a shiny, smooth paste.
Using a piping bag, lay thick dough ‘sausages’ 6-7cm long on a baking sheet covered with greaseproof paper.
Mix the egg yolk with the 2 tablespoons of water. Glaze the ‘sausages’ with a brush. Place the baking sheet in the oven and cook for 10 minutes at 220°C, and then continue cooking for 7 minutes at 190°C.
As soon as the éclairs are cooked make 3 small holes along their backs. Fill the piping bag with cold light cream, top the éclairs according to the selected flavour (rose, violet, and pistachio) and then place them back on the sheet.
Pour the sugar into a bowl and gradually add the water without stopping stirring.
The mixture should be quite thick.
Add the food colourings.
Apply immediately to the éclairs.