AI decided to bite and bought the recipe yesterday based on several good reviews here. I'm sure I followed recipe to the letter as she had indicated. The only adjustment made was doubling ingredients. Cake rose and overflew in the oven. By the time I brought them out, everything sank. Could anyone kindly tell what I did wrong. Please and thank you.

AThe majority of the issues with that recipe stem from the reverse creaming step.

Just be sure your ingredients are at least somewhat brought to room temp (at least just not super cold), and mix on medium high to high for at least the 90 seconds. No butter chunks should be visible, and the batter should visibly and audibly thicken.

It could also just be a simple matter of filling your pans too full.

AI filled haif way. I used 3 different sizes of pans one of which was a 3 inch , that one ran over too!

AI meant 3 inch high

When doubling a recipe, you can't always just double everything.  RLB, in The CakeBible explains how to adjust the leavening when scaling up recipes.

AI have upped this recipe 10-15 times up with no ill effects.

I think you are having a technique issue with the reverse creaming.

I have doubled this recipe many times without adjusting the ingredients (the all whites and also the chocolate version).  For me, doubling makes 3 perfect 9" layers, and my pans are 2" high. I double it far more often than not.  (The recipe as written makes 2 thin 8 or 9" layers).  I have never had any problems with this recipe and I have played with it a lot.  As mentioned above, make sure everything is room temp. and cream the full 80 seconds before continuing.  Any chance you added one of the leavenings twice?  Hopefully another try would work.  It is a really lovely cake.  

AThanks all for responses, I plan to give it another trial throw with another can of bkg powder, Have a wedding coming up in January .