Hello I bought the holiday fir tin to make the Spruced Up Vanilla Cake. The first time I mixed all the ingredients in the food processor and baked it at 180 for 45 mins. It was quite dark on the outside but the inside looked quite doughy at the edges even though the the tester was clean. The second time i adjusted temp of oven as mine is fan to 160. I mixed the ingredients in the stand mixer and baked for 55 mins but still looked doughy when cut as if needing more time to cook yet tester came out clean. Any suggestions would be great. Many thanks.
The baking time of Nigella's Spruced-Up Vanilla Cake will vary slightly as all ovens vary and also the shape of the tin will affect the cooking time. It is certainly likely to be that you need to turn a fan oven down by 20c (from 180c to 160c) and you should always check your oven handbook as this will give guidelines for any adjustments that are needed.
If a cake tester is coming out clean the the cake should be cooked. However the cake should also feel firm to the touch on the surface and may be pulling slightly away form the sides of the tin. From the description of the second cake it sounds as if it is also possible that the cake has been slightly over-mixed. The texture of the cake is not as light as a Victoria sponge but it should not be dense or doughy. You could try adding only half of the flour after adding the eggs, then adding the yogurt, bicarbonate of soda and vanilla, and finally folding in the remaining flour. Also although there is not much raising agent in the cake, do make sure that your bicarbonate of soda is still within its "best before" date, as it will become less active over time.