You have a few options: 1. Use a skewer to test, it should come out wet from the centre. 2. Bake 1 as a test pudding and time it, test it by turning it out and seeing how molten it is inside. If you want more gooey, cook a few minutes less, or more if it seems too raw. 3. Check out the photos for reference, the tops should be set but feel soft to touch in the centre, if they start to rise up in the middle creating cracks like a muffin they are over cooked.