Spread the ice cream over the slices of panettoncini. Put the panettoncini back together, cover and freeze for approx. 1 hr.
Bring the orange zest, juice and preserving sugar to the boil, simmer for approx. 20 mins. and leave to cool. Stir in the amaretto.
Beat the egg white with the salt until stiff. Add half the sugar and continue beating until the mixture turns glossy. Add the remainder of the sugar, briefly continue beating. Remove the panettoncini from the freezer, transfer to a baking tray lined with baking paper. Spread the egg white over the top using a spoon.
To cook the meringue
Approx. 2 mins. in the centre of an oven preheated to 240 °C (top heat). Remove, cut in half, serve immediately with the orange sauce.