What is your go to chocolate recipe for a sheet cake?

Are you looking for scratch or doctored mix recipes?

CC member contributed scratch cake recipes:
(Includes "chocolate".)

http://cakecentral.com/cake-decorating-ftopict-440803-.html

Everything you need to know to make, decorate and assemble tiered/stacked/layer cakes:

http://www.cakecentral.com/cake-decorating-ftopict-605188-.html

Above superthread includes popular CC recipes for crusting American buttercreams, several types of fondant and doctored cake mix (WASC and other flavor variations) - and so much more!

HTH