Beat the egg whites with the salt until stiff. Add half of the sugar and continue beating until the mixture turns glossy. Add the remaining sugar, continue to beat until the mixture is fine-textured, glossy and very stiff. Transfer one third of the mixture to a piping bag with a round nozzle (approx. 12 mm in diameter), set aside. Using the rest of the egg whites, spread two circles (each approx. 20 cm in diameter) on two trays lined with baking paper. To make the ghosts, use the piping bag to pipe tear-drop shaped blobs next to the circles (each approx. 3 cm in diameter).
For the meringue ghosts, melt the chocolate in a bain-marie. Draw faces onto the cooled meringue ghosts using a chopstick or thin brush.
2 - 2 1/2 hrs. in an oven preheated to 100 °C (convection/fan), propping the oven door ajar with a wooden spoon. Leave the meringue to cool.
Bring the sugar and water to the boil in a wide pan without stirring. Reduce the heat and simmer, swirling the pan occasionally until a light brown caramel has formed. Remove the pan from the heat. Add the butter and stir to melt. Add the cream and salt, bring to the boil while stirring, turn down the heat. Over a low heat, reduce to a thick sauce, stirring constantly. Transfer to a bowl, leave to cool.
Beat the cream until stiff, fold in the vanilla paste.
Place one of the meringues on a cake plate, top with half of the whipped cream, nuts and caramel sauce. Cover with the second meringue, top with the remainder of the whipped cream, nuts and caramel sauce. Decorate with the meringue ghosts.