Combine sugar with 1/4 cup water and cook stirring till it forms a thin syrup.
Remove from fire and add lime juice.
Place 1 slice of cake on an oven proof plate. Pour 2-3 tbsp of syrup over it.
To prepare the meringue, beat the egg whites till stiff. Gradually beat in 2 tbsp of sugar.
Add the essence. Mix remaining sugar with icing sugar and fold into the whites.
Using a tea spoon, form a thin border of meringue around the side of the cake slice on the plate. ( This will prevent the jam from oozing out during baking. )
Fill the centre with mango jam. Cover with the other slice of cake. Pour a little syrup on top.
Cover the entire cake with the remaining meringue. Sprinkle cashew nuts on top.
Place under a grill till light brown on top. Serve warm.