Preheat oven to 180 degrees C. Grease and flour two 20cm round cake tins or one 23x33cm cake tin.
In a medium bowl sift together the flour, bicarbonate of soda, salt, cinnamon and nutmeg. Set aside.
In a large bowl cream together the butter and sugar until light and fluffy. Blend in the applesauce. Beat in the eggs one at a time. Beat in the flour mixture, mixing just until incorporated. Stir in the sultanas and walnuts. Spread mixture into prepared cake tin.
Bake in the preheated oven for 25 to 30 minutes for the two 20cm round cake tins or 35 to 40 minutes for the 23x33cm cake tin. The cake is cooked if a toothpick comes out clean when inserted into the centre of the cake.
Cool in the tins for 5 minutes before turning out onto cake racks. If using icing, cool completely before covering the top of the cake.