I baked a cake and the bottom half of it for some reason is partially cooked and a bit hard but the top is perfect and spongy, baked it as I usually do. Tried it again and the second time the same thing happened. the oven seems to be working fine. never happened before, any idea what went wrong? thanks xx

Is it a new recipe? Try baking another recipe in the same pan to see if it does the same thing. 

Also - what size pans are you using? 2 inches high or 3 inches high?

I find my 3 inch high pans don't bake certain recipes well. Some of my recipes I have found sink in the center. They bake perfectly fine around the edges and top, but the center is under baked - even if a knife or cake tester comes out clean!

its the same recipe i use every time and the pans are also the same their all 3" high, the skewer did come out clean. ive even got the oven checked out and it seems fine so im abit confused what could it be? :( 

It's probably your pans. They're too high and sort of steam the cake - especially if there is a lot of liquid in the batter. Try switching to 2 inch pans or only filling the 3 inch pans partially. They should bake more evenly. As I said before, there are only a couple recipes I am unable to bake in my 3 inch pans. 

thanks so much. Also at what temp do you bake ur cakes and for how long? thanks 

350 degrees. If I bake a full 3 inch cake, it usually takes about 1 hour. I usually check for done-ness around 45 minutes.