In a large bowl whisk the egg whites to the stiff peak stage.Then whisk in the sugar – roughly a tablespoon at a time. Next take a metal spoon and lightly and gently fold in the ground hazelnuts. You can also watch how to whisk egg whites in our Cookery School Video on the right.Now divide the mixture between the prepared tins and spread it out as evenly as possible. Place the meringues near the centre of the oven and reduce the temperature to 140°C, gas mark 1. Allow them to cook for 1 hour, then turn the heat off and let the meringues cool in the oven.When they’ve cooled, loosen them round the edges with a palette knife. Place the base of each tin on an upturned bowl and just slide the tin downwards. After that use the palette knife to slide them onto a flat surface.While the meringues are cooking, prepare the filling. Place all the ingredients (reserving half the orange juice for later) in a shallow pan, bring them up to simmering point then simmer gently for 30 minutes without a lid. After that, remove it from the heat, and when it’s cooled remove the cinnamon sticks and the orange zest. Whizz half the mixture to a purée with the reserved orange juice in a mini-chopper.Then combine the purée with the rest. To fill the meringues (which can be done up to 2 hours before serving), whip the cream to the soft peak stage, then carefully spread the cooled apricot mixture over one meringue, followed by half the whipped cream. Then, carefully, position the other meringue on top. Spread the remaining whipped cream over that and decorate round the edges with whole toasted hazelnuts. Use the base of the cake tin to transfer it to a serving plate.Then store covered in the fridge until needed.Note: the meringues can be made several days ahead and stored in a tin, and freeze very well too.