This simple buttercream recipe is from The Whimsical Bakehouse by Kaye Hansen and Liv Hansen.  It is not based on a sugar syrup, so is easier to make.  It holds up very well and has a neutral flavor that begs for variations.  This is the frosting to use on a hot day.  I will go on record as saying that I prefer "true" buttercreams, but they won't hold up on a hot day.  This one is easy, makes a lot, holds well on a hot day, takes color well (should you want to do that) and has a neutral "bakery icing" flavor.

While this recipe contains 10X sugar, the boiling water mostly counteracts that sort of chalky-thing that can happen with this type of sugar.  This recipe makes kind of a ton, so make sure you have a stand mixer with at least a 5 quart capacity.  Or, you can halve the recipe.

6 cups sifted 10X sugar
1/2 teaspoon salt
1 teaspoon vanilla
3/4 cup-1 cup of boiling water (depending on humidity)
2 3/4 cups vegetable shortening (not oil--the solid white kind)
6 oz. cool butter, cut into little pieces

In the bowl of your stand mixer fitted with the whip attachment, stir together the sugar and salt.  Add the boiling water and whip on medium speed until smooth.  Add the vanilla, shortening and butter.  Increase speed to medium-high, and whip until light, fluffy and doubled in volume.  This could take 10 or 20 minutes, so be patient.  Flavor with liqueur or extract.  You can try adding chocolate, but I haven't so I'm not sure how good it would be.  If you try it, let me know.