What to do if my cake seems ready from the outside (it's brown as it should be) however it's not done yet inside? How do i really know that my cake is done?
If you find that your cakes are brown on the outside but are still raw on the inside then it is likely that the oven is too hot. Most cakes are baked at around 180c/350F/Gas Mark 4 on the middle shelf of the oven. It is worth checking that your oven is running at the correct temperature using an oven thermometer (they are usually inexpensive). Put the oven thermometer into the oven in the centre of the middle shelf and once your oven has preheated check it is showing the same temperature as you oven's own temperature gauge (use oven gloves or mitts to handle the thermometer as the metal will be hot). If the oven is running too high then you may need to turn it down slightly. Some ovens also have hot and cold spots so you may need to rotate the cake tins (pans) part way through the cooking time to ensure even cooking (usually just after the halfway point in the baking time when the cake is looking set on top).
A properly cooked sponge cake should be golden brown and also risen. Carefully touch the centre of the cake with your fingers, it should feel firm and slightly springy. Also the cake should be slightly shrinking away from the sides of the cake tin (pan). You can also check the cake by inserting a thin skewer, cake tester or cocktail stick (toothpick) into the centre of the cake. If the cake is fully cooked then the skewer will come out clean, if there is raw or partially cooked batter clinging to the skewer then return the cake to the oven for a further 5 minutes and test again. For rich fruit cakes the skewer test is the best way of checking that the cake is cooked all the way through.