I love all things lemon, so my favorite cake is lemon topped with lemon buttercream. I'd like to take my lemon fav over the top with a filing of lemon curd. Has anyone used a store bought lemon curd for a filling between layers without refrigerating the cake? I'm wondering if I can minimize any concern about room temperature in finding a brand packed full of preservatives. 
I know! It goes against everything the average baker holds near and dear in terms of "fresh" but.... Any ideas?
How long does it need to be at room temperature? I use lemon curd all the time, and it's never been a problem, but I keep my cakes cool until they are delivered.
Store bought lemon curd isn't even the same thing as home made, it's super sweet and a weird thick grainy texture.
If it has to be at room temp for a really long time, I would just do the lemon buttercream, and maybe candy some finely grated lemon zest. It adds a neat texture element, and is super lemony.
Store bought lemon curd is nasty. I have seen cake supply stores sell it in sleeves. I do t know if it's any better. Why not make your own? ItS not difficult.
I've used both store-bought and homemade, and I prefer the homemade. However, if you're concerned about longevity of your homemade lemon curd, try an eggless lemon curd. You can google and get a few recipes. It's dead easy and has a longer life than lemon curd made with eggs. You may find it very tart, but you can mix some buttercream with it if you're using it as a filling, and it sweetens it up somewhat. I used it to fill a lemon/blueberry cake recently, and everyone loved it.
Thank you, ladies, for your input. I was thinking store-bought because of preservatives; the potential to leave the cake out on the counter for a couple of days (depends upon the household - crazy us -we gobble it up here pretty quickly) without fear of spoilage.
You've piqued my curiosity, Kathleen. I had no idea there were eggless versions. As for tart, that's the point - the contrast to the lemon buttercream. Sounds good to me!
but in lemon curd you cook through the eggs, so it should be edible and fresh for the same time your buttercream would be held on RT. I have held my home made lemon cream on RT for app 12h and it was still good and didn't cause any problems :)
Holding for 12 hours is not the problem.
Holding for three days while you decorate, plus whatever days the customers holds after the party, is not safe.
Neophyte, this is the recipe I used.
http://www.grouprecipes.com/38383/eggless-lemon-curd.html
However, there's quite a few out there. It's just a matter of picking one, which is pretty much what I did. 
As I mentioned, it was very tart, so I mixed it with a bit of SMBC (taste-testing as I went) for the filling. Once filled, it was going to be almost 3 days (most of it in a refrigerator) before the cake was going to be eaten, but I felt comfortable that the filling would be just fine.
As a side note, I make my SMBC with cartoned egg whites, so I wasn't concerned about that either. :-)
Kathleen, you're a lady who thinks the way I do. I've yet to try SMBC for the egg whites in that, too. I like the idea you are happy enough with a boxed white version. May I ask which brand of the whites you buy? Seems there are so many things to try but so little time. And I have to be mindful of the waistline as I never runs "tests" on others. If someone's going to get sick or say, "ICK!", it'll be my honey and me. 
This is the reason I love CakeCentral - others are trying new things, too, offering tricks and tips. Thank you again to all!
I also use egg whites from the carton, but I buy my grocery store generic brand. I've made SMBC using brand name egg whites, but it tastes the same to me when I use generic.
I buy whatever brand is the least expensive when I'm at the grocery store, either in the 250 ml or 500 ml carton, depending on how much icing I'm making. If I ever get into this major seriously, I'll eventually buy them in the big box club store in the litre carton. What's nice is that they can be frozen. Once.
Here is a recipe that has been tested and is safe.
Lemon Curd
The following recipe has been tested by Food Safety Net Services. Its pH and water activity (aW) levels qualify it to be a "Non-Potentially Hazardous Food" as defined by Texas law.
You must follow this recipe exactly to obtain the same result. If you use a different recipe for lemon curd that you wish to sell, you must have it tested to be assured that it is a Non-Potentially Hazardous Food that does not require refrigeration. We are not responsible for your results with this recipe. It is provided to you for free, without any guarantee or warranty of any kind.
Lemon Curd
pH 3.39
aW 0.90
Tested 12/9/2011 by Food Safety Net Services
Ingredients
4 lemons, at room temperature
1 1/2 cups sugar
1/2 cup (1 stick) lightly salted butter, at room temperature
4 eggs, at room temperature
1/8 teaspoon salt
Remove the zest of the lemons with a microplane grater. After zesting, squeeze the lemons to make 1/2 cup of juice and set the juice aside. In the bowl of an electric mixer fitted with a paddle attachment, cream the butter with the sugar and lemon zest. Add the eggs, 1 at a time, and then add the lemon juice and salt. Mix until combined.The mixture will look curdled at this point.
Pour the mixture into a saucepan and cook over low heat, stirring constantly with a whisk, until thickened, about 10 minutes. It will thicken at about 175 degrees F, or just below a simmer. Do not boil. Remove immediately from the heat. It will thicken after refrigeration.
These recipes were tested at the personal expense of Texas Cottage Food Law. If you found these results helpful, please consider a donation to help offset our expenses.
Quote by @%username% on %date%
%body%