The first time I baked the Old-Fashioned Chocolate Cake it turned out beautifully. Each subsequent time it rose in the oven but dropped considerably once taken out. I followed the food processor method. The first time the cake was risen and light with an even crumb and moist texture. After that it was visibly less risen and light, with a wetter looking middle layer and uneven crumb with too moist a texture. The outside was hardened and looked as if to burn. The skewer was clean each time when removed.The oven was on 180 non fan, I baked it for 35 minutes. What did I do wrong? Over mixing? It did take quite a bit of processing to break up the room temperature butter, could I use margarine instead? Oven too hot? Help! I am a novice baker but his cake was so delicious the first time that I have vowed to make it every week until I conquer it!
Nigella's Old-Fashioned Chocolate Cake (from Feast and on the Nigella website) is a very popular recipe. From the decription of the cake, with a hard crust on the outside and a wet, underbaked middle, it would suggest that the oven is maybe on the hot side. However afer 35 minutes the cake should be cooked through rather than wet in the centre. Nonetheless it may be worth checking your oven temperature with an oven thermometer. These are not expensive and can be bought from hardware and baking stores and also on-line.
It is also possible the the cake has been processed too much. If the butter and sugar are mixed too much then the sugar can start to liquefy and that makes the cake batter more liquid and also the butter starts to melt, making the batter loo liquid and greasy. It may be that the butter was slightly too cool and then required a lot of mixing to incorporate it. Butter should be at 20c to 25c for cakes and when you press a clean finger into the butter it should be easy to make an indentation, but the butter should not be so soft that it feels greasy. Finally make sure that you measure the baking powder and bicarbonate of soda (baking soda) carefully as too much leavening can cause the cake to rise up in the oven but then sink back dramatically on cooling. Use a proper 5ml measuring teaspoon and 2.5ml half-teaspoon and use level measures.