Lemon and white chocolate mousse: Heat the lemon juice over low heat in a saucepan.
Meanwhile, beat the egg yolks, whole eggs, and sugar in a bowl, then pour in the warm lemon juice.
Return the mixture to low heat and heat until thickened, stirring constantly with a spatula to prevent the cream from sticking to the bottom of the saucepan.
Off the heat, incorporate the butter and white chocolate in small pieces.
Mix well, transfer to a container, cover with plastic wrap, and refrigerate.

Whip the 35% cream until stiff.
When the lemon cream is well chilled, gently fold it into the whipped cream with a spatula.

Melt the chocolate in a double boiler with a few drops of neutral oil.
Meanwhile, fill a pastry bag with lemon and chocolate mousse, then place a first layer at the bottom of the verrines.

Fill another pastry bag, fitted with a fine tip, with melted dark chocolate and pipe thin strands over the first layer and lightly over the edges of the verrines.

Add a second layer of mousse and finish with melted chocolate.
Refrigerate and serve the verrines well chilled.