I made a good homemade recipe today.  Tastes great.  But they sunk in the middle.  Used baking strips, flower nails and baked at 325.  I can fill with buttercream but I want to learn fondant too and you cannot hide a sunken place to well if you use fondant.  Why do you think this is happening.  Does it with doctored mixes too.  Great new oven.  Works great. 
I am stumped.
 

Is the center of the cake done? Have you checked to make sure your oven temp is correct? Place an oven thermometer in the oven and most likely your oven is off by about 25 degrees new or not. If it's baking to high it will set on edges before it sets in the middle, making the cake sink. Also, don't out rule the recipe being a dud. Try another! 

The recipe is from Roland Winbecker.  I have had the same trouble with WASC too.  Even with old oven.

AI have been having great success with Beyond Buttercream's white cake recipe and I also made Paula Deen's 1 2 3 4 cake this weekend as I had some self rising flour I needed to use up and it got rave reviews.

AHere's beyond buttercream recipe , I've never tried it but have heard wonderful things about it.

fromscratchsf.wordpress.com/2011/07/26/white-cake-part-3-with-recipe/

I use Beyond Buttercream's cake recipe as my go-to recipe and love it.  So far, have never had a problem with it as cake or cupcakes.  Highly recommend it.

just a tip, make sure your leavening agent is fresh and use the exact amount. too much leavening can make your cake sink too. 

Also, make sure you don't open the oven door too soon.  I let the cake bake at least 35 minutes before checking on it.