No Shortening and No Refrigeration, Buttercream Frosting

The ingredients they post are:

• 1 cup solid vegetable shortening
• 1 teaspoon Wilton Flavor (vanilla, almond or butter)
• 7-8 teaspoons milk or water
• 1 lb. confectioners' sugar
• 1 tablespoon Meringue Powder
• pinch of salt (optional)

I would make the following suggestions based on these ingredients:

• It's not really butter cream icing if you're using vegetable shortening. You'll get far superior flavour by using butter. Pure butter may have trouble holding its shape, but you should have no trouble at all switching to a half-and-half mixture. This ratio won't change the colour much either.

• I've never personally cared for the Wilton flavourings and suspect that is a major part of the problem here. If you're using the vanilla, it's not real vanilla, it's imitation vanilla extract; pure vanilla extract is dark brown and would colour the icing. Their almond flavour also seems to taste nothing like normal almond extract, and the butter flavour is thoroughly pointless (just use butter!).

  You can use real vanilla extract, but it will definitely darken the icing. You can try to compensate with an icing whitener, but those things are intended for slightly-off-white icings and probably won't get you all the way to white. Alternatively, you can use pure almond extract instead of the imitation; it is actually clear to begin with.

  Or, better yet, you can just change your brand. Lorann makes a bunch of concentrated flavouring oils that might taste less fake. If you go to any baking supply store you'll probably see other brands as well. Try a few until you find one that you like.

• You don't say whether you're using milk or water, but use whole milk or even cream if you can; don't miss an opportunity to lay on the fat (and therefore flavour).

• Finally, a lot of people (me, for example) find the taste of meringue powder to be disgusting. You don't need it, and the vast majority of buttercream icing recipes don't contain it.

  If you really want a meringue-based buttercream, as opposed to a simple buttercream without any egg products at all, then just go for broke and make it from an Italian meringue; whip some egg whites to soft peaks, then whip boiling sugar syrup into the eggs until the mixture stiffens, and afterward incorporate the butter and other flavourings.

  I know, they're going to tell you that it won't be stiff enough. But stabilizing a meringue is dead easy; just bloom some gelatin in the cold liquid (water/milk/cream) before you incorporate it¹. The more gelatin, the stiffer it will get. Don't overdo it because if you add too much gelatin, you won't even be able to get it out of the bag (this has happened to me). A 1% ratio should be plenty.

Making a great-tasting decorating icing is easy. Stiffness isn't usually the problem, colour is. If you want brilliant white icing then you have to make certain tradeoffs. If you're willing to settle for a cream colour (or slightly whiter, with a whitener) then you've got nothing to worry about.

_{1. If you're not starting with a hot meringue, then be sure to heat the liquid with bloomed gelatin to dissolve before adding it to the icing!}

Most vegetable oils are predominantly some type of unsaturated fatty acid - that is, monounsaturated or polyunsaturated. This type of fatty acid is a liquid at room temperature ("oil"). On the other hand, saturated fat is a solid at room temperature, which is easily demonstrated with butter or animal fat (lard) - which are primarily what vegetable shortening is supposed to substitute for.

Wikipedia has a breakdown of the various types of oils and the proportions of fat types. What's important to note is that while the majority of oils have little to no saturated fat, palm oil in particular is approximately on par with butter, and coconut oil is actually higher than margarine (the most common hydrogenated vegetable oil product).

In fact I've actually never heard of "coconut [oil] shortening" - the idea baffles me because coconut oil is already quite solid at room temperature. It doesn't need to be processed any further to be used as a substitute for butter or vegetable shortening. It's not quite so simple with palm oil though, and there is a "palm shortening" which is different from palm oil.

Hydrogenation is, in a nutshell, converting unsaturated fat to saturated fat by adding hydrogen. Most of the time the hydrogenation is not 100% complete which also leaves trans fats. Palm oil isn't quite as solid as coconut oil so it does need processing in order to be used as a shortening, but hydrogenation is not required; all that needs to be done is to separate the saturated (solid / stearin) fats from the unsaturated (liquid / olein) fats. This is done through crystallization, which is completely different from hydrogenation.

Some companies may indeed also put the coconut or palm oil products through an emulsification process to add volume or make it easier to work with, but that is entirely incidental; these products are made solid due to the very high amount of pre-existing saturated fat and the removal of all or most of the unsaturated fat.

To sum it all up, it's not hydrogenation that makes fat solid at room temperature, it's saturation (of hydrogen atoms), and hydrogenation just happens to be one way to achieve saturation. For products already containing plenty of saturated fat, hydrogenation would be redundant.