Ok soo.... been baking for a while now but never tried baking a carrot cake from scratch. Found a recipe for it at a Le cordon bleu book. Since its my first time trying I decided to try with a few cupcakes and if it works use the rest of the batter to do a small cake,  they're gummy at the bottom! What can I do to fix the rest of the batter so it doesn't turn gummy like the cupcakes?  Did I do something wrong?  What can it be?  Help! ! 

You might have overmixed the flour. It's very important to sift in the flour to avoid lumps, and only mix it with a hand whisk, not a mixer, until it's JUST incorporated.

If you mix it for too long, the gluten in the flour will form long strings of protein, and your cake might turn out gummy. You definitely want this effect in bread, that's why it's kneaded so long. But not in your cupcakes. 

Maybe it was your recipe? Here's a carrot recipe that I've tried and tested: 

http://backtobasics-marilyne.blogspot.ch/2011/06/carrot-cake-swiss-version.html

Good luck and happy baking!

might not be mixed correctly or an incorrect measurement of ingredients and sometimes cake recipes do not translate into cupcakes and vice versa

check other carrot cake recipes and see how does yours stack up--is it approximately the same amount of ingredients give or take?

and did you follow the directions carefully? is this an oil based cake? if not did you melt the butter?

and carrots are loaded with liquid--might just be the extra liquid? how did you grate them?