How to prevent your cake mixture from curdling
Curdling occurs when the butter and sugar have not been creamed sufficiently (until light and fluffy) to form a strong emulsion to absorb the eggs. Also, if cold eggs straight from the refrigerator are added to the mixture too quickly, separationwill occur. A curdled mixture holds far less air, so the cake will be flat.
Have the eggs at room temperature and add them gradually. Adding a teaspoon of flour with each of the additions can also help to prevent curdling. If the mixture does start to curdle, briefly dip the base of the bowl into warm water and whisk to restore the light consistency.
How to prevent airholes and cracks in your cake
Holes are caused by overmixing or by uneven or insufficient folding in of the flour. The mixture should be soft and dropping after folding; if it’s too dry, pockets of air are likely to be trapped. This also happens if the flour and raising (rising) agent are not sifted together thoroughly.
To prevent cracking, be sure to use a tin of the right size and check that the oven is not too hot. Place cakes in the centre of the oven, not too high up where it will be hotter and the cake will peak and crack.
How to prevent your cake from sinking
Cakes will sink if they have not been baked long enough, so follow the time stated in the recipe and use a timer. Don’t be tempted to open the oven door during cooking. Using too cool an oven, or opening and shutting the oven door during baking will cause sinking, as will too much raising (rising) agent in the cake mixture.
Cakes are ready when they are firm in the centre and have shrunk away a little from the sides of the tin; sponges should spring back when pressed lightly with your finger.
How to tell when your cake is cooked
Insert a wooden or metal skewer deep into the highest part of the cake and take it out immediately. If small residues of mixture stick to the skewer, the cake is not yet done. If there is nothing on the skewer or only individual crumbs, the cake may be taken out of the oven. Be careful if there are pieces of chocolate in the cake. Chocolate always sticks to the skewer; it does not set until it has cooled down.