For the rolls with lavender snow, first prepare the filling. For the filling, the day before, bring milk with lavender sugar to a boil and let stand covered so that the aroma develops in the milk.
Roll out the puff pastry on a floured kitchen board to a thickness of 3 to 4 mm and cut into 3 cm wide strips.
Butter the metal funnels provided for foam rolls, wrap the pastry tightly on them so that the pastry strips overlap by half a finger’s width.
Brush with beaten egg, place in rows on a baking sheet with parchment paper and bake in a hot oven until golden brown. Once done, remove from molds while still hot and let cool.
For the filling, strain the lavender milk and bring to a boil. Mix the whipped cream with the egg yolks, sugar and starch, then pour into the hot milk and heat, stirring constantly, until the mixture thickens.
Remove from heat and fold egg whites, beaten to snow, loosely into the mixture. Fill the dough rolls with the cooled cream. Insert a sprig of flowering lavender into each for decoration.