Some of the cakes in our collection are cooked with a collar. This extends the height of the cake, giving a more dramatic result—the basic fruit and mud cakes are cooked with collars to give extra height and protection during cooking.
The basic carrot cake also requires a collar if you are using a 20 cm (8 inch) tin rather than a 22 cm (9 inch) one. This is because you are putting the mixture into a smaller space and it would overflow out of the top of the tin.
As a general rule a single layer of baking paper is enough for a collar on an average-sized cake. Larger cakes and fruit cakes will need a double layer of baking paper to make the collar and line the base.
To make a collar, lightly grease the cake tin. Cut a strip of paper long enough to fit around the outside of the tin and tall enough to extend 5 cm (2 inches) above the top of the tin. Fold down one cuff, about 2 cm (1 inch) deep, along the length of the strip. Make diagonal cuts up to the fold line about 1 cm (1/2inch) apart. Fit the collar around the inside edge of the tin, with the cuts in the base of the tin, pressing them out at right angles so they sit flat around the bottom edge of the tin. Cut a circle of baking paper using the tin as a guide. Place the circle of paper in the base of the tin, over the cuts in the collar.