Welcome to the Cake Decorators Q&A

I’ve used Pauls chocolate cake recipe for making cupcakes with great success on several occasions – except for yesterday when 2 entire batches sunk in the middle and went very stodgy I wasn’t aware I has done anything different but must have for this to happen can anyone help with what went wrong this time. Thank you

I made this cake for the first time this week and really pleased with results. I Halved ingredients as was making 8 in cake, but forgot to half the bicarbonate of soda! There was only a slight dip on the middle and it tasted fabulous. Perhaps my little mistake prevented this.