1) Cut to measure the sponge cake and place it in the mould.
Soak with the orange liqueur and place to one side.
2) Topping: in a saucepan whip the eggs with the sugar to a froth, then add in the flour and melt in while gradually pouring in the milk, already heated, mixing well to prevent the formation of lumps. Place the saucepan on the heat and, still mixing, thicken the topping by cooking it for 2 minutes. Remove from the heat and add the isinglass soaked in cold water and well-squeezed, then flavour with the liqueur and leave to cool. Mix in the yogurt and pour the topping onto the sponge cake base. Place the charlotte in the fridge for 6 hours. 
3) Decoration: a little before serving turn out the charlotte onto the serving dish, coat the Sfogliatine glassate Balocco with the apricot gelatin and make them stick to the edge of the charlotte by securing with a ribbon.
Complete the decoration with a rich fruit salad of sliced fresh fruit.
An extra tip:
Instead of the sponge cake you can use Savoiardi Balocco to spread over the base of the mould: make sure however to compact them carefully and uniformly before pouring on the topping which must be reasonably solid.