Sift the granulated sugar. Crush the hazelnuts very small (best results in a blender). Wash the sultanas. Wash and grate the carrots. Grease the cake tin (9 by 12-inch deep).
Place a bowl over a pan of hot water. Preheat oven to 350 degrees F. Into a warmed bowl place the egg yolks and 4 ounces of the granulated sugar and whisk together until the mixture thickens. (It should be doubled in bulk, lighter in color and creamy in texture). When this happens, set aside the yolk and sugar mixture for a moment (off the heat). Into a clean, cold bowl place the whites of eggs, add 1 teaspoonful cold water and some freshly ground salt and whisk quickly until they are stiff and peaked. Gradually beat into the fluffy whites of eggs the remaining 6 ounces of granulated sugar until it is fully incorporated. Set aside until required.
Place the egg yolk mixture over the warm water and add the ground nuts and lemon juice. To this add the grated carrots and lemon zest. Fold in the 1 teaspoonful of flour and sultanas.
Remove the bowl from the heated water. Fold in 2 tablespoonfuls of egg whites. Then put all the mixture into the remainder of the whites of eggs and fold in well.
Add the 1/4 teaspoonful of cinnamon.
Pour all the mixture into the greased cake tin and put it into the preheated oven set at 350 degrees F., on the middle shelf, for 60 minutes.
Remove cake from the pan and cool completely.
Cut cake in half, spread the jam over the bottom and replace top.
Sprinkle with confectioners' sugar before serving.
