Cooking large cakes is different than cooking smaller cakes. Each tier on a large cake is typically made from two, 5 cm (2 inch) thick layers of cake. The cooking time for a large cake varies with the size of pan used. You can cook up to 40 cm (16 inch) cake pans in most ovens. If your oven is small, check the size of the pan to make sure the door can close with the pan inside the oven. If this is your first time to make a large cake, plan to make a trial cake a while in advance to prevent a last-minute disaster.
Place a sheet of parchment paper in the bottom of each cake pan. Spray the top of the paper and the sides of the pan with cooking spray to prepare the pans for baking. Heat the oven to 163 degrees Celsius (325 degrees Fahrenheit) for best results. Higher temperatures will cook less evenly and make the cake too rounded.
Use 2.133 litres (9 cups) of batter for a 30 cm (12 inch) round cake, 2.844 litres (12 cups) for a 35 cm (14 inch) cake and 3.792 litres (16 cups) for a 40 cm (16 inch) cake. For large sheet cakes, use 2.133 litres (9 cups) of batter for a 40 cm 27.5 cm (16 inch by 11 inch) cake and 14 cups for an 18-inch by 12-inch cake.
Fill the cake pans with the correct amount of batter and tap them gently on the counter to remove air bubbles and even the level of the batter.
Bake the cakes one at a time in the oven, placed on the centre rack. Air circulation is important to help the cakes bake evenly.
Cook the cakes based on the size and amount of batter. Cook 30 cm (12 inch) round cakes for 50 minutes, 35 cm (14 inch) cakes for 55 minutes and 40 cm (16 inch) cakes for 60 minutes. Cook sheet cakes based on size as well. Cook 40 cm by 27.5 cm (16 inch by 11 inch) cakes for 30 minutes and 45 cm by 30 cm (18 inch by 12 inch) cakes for 40 minutes. The cakes may need more time. Remove the cakes from the oven when they are spongy in the middle and start to come away from the sides.
Cool the cakes for 15 minutes on wire cooling racks before moving to the freezer to prepare for icing.