Preheat your oven to 180 ° C. Mix the flour, sugar, salt and yeast in a bowl.
Separate the white from the yellows.
Whip the egg yolks, the fruit juice, the grape seed oil.
Add the mixture with the flour and mix quickly until you obtain a homogeneous paste.
Beat the egg whites and incorporate them into this mixture.
Butter your mold 20 cm. Pour the dough and bake for 50 minutes to 1 hour.
Let the cake cool for 10 minutes.
Unmold and let cool on a cake rack.
Pack in food film and place in the refrigerator.
Prepare the butter cream by mixing the soft butter, the icing sugar and the vanilla extract with the robot.
Unpack the cake
Spread butter cream on the sides and top.
Repack in food film and then refrigerate for at least 1 hour before covering with sugar paste.