As to how long to cook it depends on the doneness of your cake. I agree with nutcakes. If the edges are getting brown but the center is still not done, I shield the edges with foil to prevent further browning but still allow the center to cook. I personally would not lower the oven temperature because sometimes in doing that it can cause the cake to sink in the center. You might want to check and be sure your oven is cooking at the correct temp. and that it is not cooking higher than you have it set for, which will cause done edges quite quickly but the inside will still have a ways to go. My oven was cooking 25 degrees higher that I had it set for, and when I realized that, I reduced my temperature 25 degrees less that the recipe states and my baked goods turned out perfect!

first time I've ever heard of one. sounds interesting. thanks!

Do you know what a cake breaker is? Merrill wrote about it in theis recipe:
http://www.food52.com/recipes/4719_angel_food_cake_with_heath_bar_whipped_cream_icing

You probably don't have one, but I think using a serrated knife to cut the pieces and a small spatula to lift them up would work.

oh, thanks for the prompt replies!

BTW, the top is intentionally crumbly.

I lower the oven 25 degrees and check every 5 minutes. Sometimes the outside cooks faster than the inside because of the high heat.

1. It really depends on how underdone the cake is. If still very wobbly, I'd give it 10 minutes, then 5 at a time after that. If firm, but the toothpick doesn't come out clean, I check each 5 minutes.

2. I just shave off the top with a serrated knife, and lift it off. Before you frost it you might like to do a 'crumb coat', where you thin a small portion of your icing a bit and do a thin layer all over. Let dry in the refigerator and the crumbs will be sealed and not mix into your final icing coat.