To prepare the pastry, separate the Egg yolks and egg white first. In a bowl combine first the yolks with the powdered sugar, lemon zest and vanilla drops and stir fluffy.
In an other bowl, add the Egg whites together with the Crystal Sugar and bit it with a mixer to a stiff snow. The sugar helps to stiffen the egg whites! To test if it is stiff enough, take the bowl with the snow and keep it up side down for a sec or two, if it falls out, then it need some more beating. ^.^
Preheat the oven to 180.
Now, add the flour to the Egg yolk mixture and stir well till smooth.
Carefully fold the white snow with a spatula into the egg flour mixture. Do not mix, but only fold it all in! Mixing would destroy the lightness of the egg snow, which is required in a good biscuit pastry!
Grab a baking tray and baking paper and spread the butter on the baking paper. Quickly continue to spread equally the pastry onto the paper, 2 cm high. Place the Roulade into the oven and bake for 12 minutes.
Once baked, turn the baked pastry still warm onto an other baking paper and carefully pull off the top baking paper.
Spread the Jam equally all over and roll the Roulade as tight as possible in. Garnish with powdered sugar.