Recipe For Cleaning Aluminum Pontoons Angel Food Trouble...?

Angel Food trouble...? - recipe for cleaning aluminum pontoons

I've tried a cake "Angel Food" from scratch and still have the same problem. The cake is on the right side well before it's time to prove that progress, (about 30-35 minutes). Even before opening the oven door, I see that he begins to sag. It is not broken, just drop an inch or less. When I made it and send the rest remains, but later, when I cut is much harder than it should be out there and feels almost damp. Its flavor is perfect, but it is soft and spongy, as I have elsewhere.

I followed the recipe exactly Alton Brown, I've downloaded, the heat from 350 to 375 in the case of my oven was off, I have 5 minutes, but every time it ends.

Any idea what we do wrong? I do not use a nonstick pan, I can not use any plastic) (glass, steel and aluminum shells and tools. Even the whipped egg whites into a container made of copper (thoroughly) cleaned. and everything is room temperature or hot, cold, nothing happens in the oven. \\ \\ \\ \\ \\ \\ \\ \\ U0026lt;br>
Thank you for the advice in advance