I made white cake in a 6" pan and 8" pan from scratch. It turned golden on outside but the very middle of both cakes was uncooked. I cooked them at 350 for about 40 minutes. Can anyone tell me what i did wrong? Is it the temperature or how much batter i put in the pan?

Hi and Welcome to CC, sugarbritches0407.

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

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

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

One of the mores is extensive baking help including links to Wilton's cake preparation and servings guide (which gives batter requirements by pan sizes as well as recommended baking times and temperatures).

Also included are member contributed baking hints and tips (inverted flower nails in place of heating cores, recipe for homemade pan grease and use of bake even strips).

There's also a trio of cake trouble shooting charts.

HTH