Can anyone explain the taste difference between BC, SMBC, & IMBC?
SMBC and IMBC taste the same, smooth and creamy. The only difference between the two is technique. Both types of icings have several different recipes - which you prefer depends upon your own personal taste. Some are more buttery, some are more sweet, some fall in the middle.
What is commonly called BC or American BC, is a combination of fat, powdered sugar, and flavor, with a bit of liquid to incorporate everything.
Which you choose is all a matter of taste, or how much labor you want to put into your icing.
I have never tried IMBC;but between SMBC and American BC, the american is a lot sweeter. The SMBC has a delicate sweetness, but is more of a buttery taste and accepts other flavors very well. I can't get enough of the SMBC with chocolate ganache added. The only drawbacks of SMBC is that is doesn't color as well and is more sensitive to changes in temperature. I prefer the taste to the SMBC, but more people are used to the regular BC taste IMHO.
JKalman taught me that I should be using oil-based candy colors, to color my SMBC. I switched, and she was right. Chefmaster and Americolor are the brands I am familiar with, although I am sure there are others.
That cake is beautiful!