Can I frost a cake with buttercream icing and leave in the counter for 5 days?
Bake a trial/test cake, you will be able to tell from there. Look at the cake as days progress, how does it look as each day goes on? Cut the cake, does it taste like something you would want to have others eat? I would be concerned with it over that period of time, but then there are egless cake recipes too. Are you using a filling that would include fruit or cream? Those are perishible, and wouldn't likely be ok after 5 days 'on the counter.' Run a trial. Best way to know for yourself.
a test is a good idea but no i would not leave a cake out for five days -- in fact i fridge all my cakes and usually just for one or two days in the final stages of production -- which is a good rule of thumb for cakes that are left on the counter -- one day maybe two but that's really pushing it -- 2 or 3 days might/probably be ok but to be safe one day --
best to you
It will likely depend on your recipe. I've had doctored mix cakes that are fine after 5-7 days (when I've had leftovers from large cakes), but a scratch cake will likely get stale more quickly, since they don't have the preservatives and emulsifiers that mix cakes do.
I generally try not to bake and crumb coat my cakes more than 3 days before they'll be served.
I agree w/K8. 5 days is just too long. I also have kept leftover cake in the frig for 7 to 10 days (for personal use only but never for a customer). You can freeze it. And magdaMI is right - no more than 3 days for paying customers :)
Is this for a customer? Don't forget that customers may expect their cake to be fresh enough that they can store it (on the counter or otherwise) for a few days before it gets stale/goes bad. I certainly wouldn't want to buy a cake that is only good the day I pick it up. If you're already pushing the limit when you hand over the cake, the customer is not getting full value.