What went wrong with this cake? This is an olive oil cake (with gluten free flour). It baked in this completely crazy way. The entire cake lifted up and there was a large bubble under the cake that shifted the batter to the sides before it cooked. 

Here's how it cooked in the pan with half removed (we used a conventional oven, the toaster oven is just for scale):



Turned the cake up in this following photo -- you are looking at the bottom of the cake this time:



A couple of questions: 


What happened?
How can we make sure this doesn't happen again?
Have you ever seen anything so crazy happen before?
I'd lower the temperature. You'll have to experiment. I think what happened is that the bottom quickly cooked and sealed. As your liquid ingredients turned to steam an air pocket was created, which would further slow the cooking of the middle.The still fluid batter would flow to the sides and provide more liquid, as the bottom rose.