I used to bake all the time - then I had kids and it's been a while. My almost 5 year old hasn't really had a birthday party with friends and we have one coming up. He loves the chocolate cake at Costco with the cream filling. I was thinking of using the Hershey's chocolate cake recipe that is on the back of the Hershey's cocoa powder and I saw a Costco-copycat cream filling. Just looking for feedback - would you suggest a different cake for an outdoor party? i'm a little worried it may be too chocolatey or not appealing enough to kids... or too hard to decorate. We will be outdoors, so I'm trying to think about that in my planning too. I've used doctored box cake mix in the past but I've often ended up with not enough batter or the layers not rising enough and thought maybe I'd try something different. Thanks for helping my anxieties with your tips! :) 

My son is a chocolate kid and he loves these chocolate cake recipes: https://joyofbaking.com/cakes/SimpleChocolateCake.html  and https://joyofbaking.com/ChocolateCake.html ok all jokes aside my son and his cousins loved the cake those recipes produce

I love the joy of baking website so i'm sure the cakes there are fabulous -- still I would vote for the one on the hershey's can -- nostalgic favorite 

I've made about a million of the Hershey's Perfectly Chocolate chocolate cakes and it is hard to beat, super moist and chocolatey.  The only drawback to this recipe is that it is very tender and not sturdy enough for carving.  As to the party being outside, I would suggest you keep the cake inside until shortly before serving or keep it in a cooler.  If you don't have a cooler large enough, you can make one using Seder Yenner's tutorial.