Grease the bottom and sides of square cake pan. Cut a piece of greaseproof paper in to fit the base exactly and grease the paper.
Preheat the top grill of the oven to 180°C.
Sift flour with mixed spice and set aside.
Beat butter and vanilla essence until creamy.
Cream egg yolks and sugar well until thick and tripled in volume.
In a different bowl, beat the egg whites until stiff.
Mix the creamed egg yolk mixture with the creamed butter and slowly fold in the spiced flour, alternating with the beaten egg whites. Carefully fold and mix well.
Take one ladleful of cake mixture and pour into cake pan.Spread mixture evenly to make about 0.5cm layer and bake under the grill for 5 minutes or until light brown. Remove pan from oven and using a skewer, prick top of cake to prevent air bubbles from forming.
Ladle another layer of cake mixture onto the baked cake and repeat this process until all the cake mixture is used up. When done, remove the cake from pan at once. Turn it over, top side up, onto a cooling rack and let cool for at least half an hour.
This is the basic technique for making layer cake. You can get creative and also use 2 different flavoured cake mixtures eg. chocolate and spice.