I recently baked a cardamom and sour cream cake. I did not over-mix - as instructed, and I baked it at the recommended temperature and correct time. I inserted a cake tester that came out clean. I iced it when it was relatively cool but once I sliced it there was a large hole in the centre and the dough around that was raw. In fact it looked like a cave in the middle of the cake. What went wrong? Otherwise the texture and taste were wonderful. Many thanks.
That sounds like a delicious cake. There are a few things you can look at to prevent this issue next time.
It might be that your oven isn't heating up or staying consistent. Try testing with an oven thermometer to make sure that your oven is getting to the right temperature and staying there.
Otherwise you can extend the baking time by a few minutes as needed. If you do this and are concerned about over baking the rest of the cake you can drop the temperature by a few (about 20) degrees as well. Or wrap the outside and top (if needed) of the cake tin loosely in some aluminium foil, this will help the center bake without over baking or browning the rest of the cake.
Test the cake with the cake tester as well as pressing the top of the cake lightly with your finger, this might help determine if there's still a gooey part hiding inside.
Hope this helps. :)