What do you guys do with your left over egg yolks when you have a large cake that requires only egg whites? I would hate to let 1 1/2 dozen of egg yolks go to waste. 

You can freeze them, Nanas.sweet.treats.  I lightly grease a plastic ice tray and put one yolk in each ice compartment and freeze them.  Once frozen, I turn them out of the tray into a Ziploc bag and return to the freezer.  Easy to remove one at a time for later use.

Another thought - sometimes when a recipe calls for six egg whites, I use three whole eggs instead.  The color is slightly more yellow, but it works fine, unless you need a super white cake.

I recalled a forum post from the past and looked it up....jeez is it really from 2008???  It has some egg yolk suggestions.

https://www.cakecentral.com/forum/t/582358/what-to-do-with-egg-yolks

So you just freeze the egg yolk as is?  I didn't know you could do that?  I thought freezing them by themselves causes them to become too gelatinous for use.  So I usually mix my egg yolks with some sugar so I can use them later to make creme brulee or ice cream.  But if freezing individually works just fine then I may start doing that.

Freckles0829, I have had no problems just freezing them by themselves.  It does change the texture a bit, make them thicker (I guess gelatinous would be a good description), but they work just fine in baked goods.  That is the only way I've used them.  I didn't know any better, and you know how they say ignorance is bliss.

I usually end up making lemon curd or homemade mayonnaise. Or giving them to my dog. 

Banana pudding and chess pie as my "go to" choices for extra egg yolks.