Baked oatmeal help

[army_mom]

Ok so I finally had the ingredients and the time to try the baked oatmeal. It looks nice until I cut into it and the middle is kind of rubbery, like cold oatmeal. Did I just not cook it long enough or did I add to much oatmeal? I cooked it almost 1 hr 15 min (big 13 x 9 pan) and the top looked done so I took it out. I used the recipe on the previous thread with 5 cups oatmeal, 2 cups water, and 2 cups yogurt plus the rest of mix ins.

I was expecting a "cake" like consistency (cross between a cake and a brownie) rather than the rubbery oatmeal one I got. Any ideas on where I went wrong? The batter was more like the batter when I make banana/pumpkin bread so I felt it would work well

Help! I'd like to try again and get it to work!

TIA.