Covering cake with marzipan or chocolate plastique

I'm looking through my cake decor books and magazines again for some ideas. One of my books is by Mich Turner called (of course) "Wedding Cakes" and in her recipes I notice that all of the cake has two layers of frosting. One is a light yellowish tan color and the other is white and I remember in another book of mine called "The Well Decorated Cake" by Toba Garrett she covered a cake with marzipan and then many layers of royal icing achieving a vrey smooth finished look. Looking further through the Mich Turner book I see that she discusses wrapping cake in marzipan or with chocolate plastique to be covered with either royal icing or rolled fondant. Her book actually says that "it is essential to first cover your cake with marzipan or chocolate plastique" and that "it will lock in moisture, provide a smooth firm base for a smart finish with your top coat, and prevents color of your cake from leaching into the icing." So even though I've had these books for some time I didn't notice this. I covered my cakes with a chocolate ganasch before putting on the fondant. Does anyone know how these layers taste on the cake? Can they go under a buttercream icing? I would imagine that the chocolate may taste better. 

Thanks Chefedb, I have to say I'm not a big fan of most TV cake shows. Toba said in her book that the use of marzipan is more of a European thing in her book. I noticed in Mich's book that she has either marzipan or chocolate plastique coverings under the outer icings quite often. She also has a quite impressive list of celebrities who have used her to make their wedding cakes. I want to taste the two along with the cake I'll be using before I decide which way to go. The last wedding cake I made had a chocolate liquer and dark chocolate ganasche under the MMF covering. It's the Ivory and blue weding cake with the white butterflies in my pictures. Thank you for getting back to me. I appreciate it.

The cake boss is a joke. Not the man... the show. That guy can do some great things with a cake. You may notice whenever they have him positioned talking to the camera there are nice wedding cakes behind him. But the cakes they put on the show are junk. Creative... but junk. Wow we can roll fondant and cover things with it. We can mold fondant into shapes. We can make the thing smoke like a build ing on fire... crap! Put a bag in his hand and ask for a nice traditional cake done in the lambeth method of piping. Any thirg grader can play with clay and playdough. The ace of cakes is no better. And the crap they're putting on the challenges on FN are usually junk! I've heard many say that the cakes in the Wilton wedding cake yearbooks are just cakes that a housewife can put together but it would seen like various piping and stringwork thecniques would have to be far harder to master that rolling fondant and molding figurines out of sugarpaste. What a joke.