Rose Levy Beranbaum's The Cake Bible is literally my cake bible. It contains recipes for the only from-scratch cakes that ever turned out any good in my kitchen, and her buttercreams & fillings are all superb. I have yet to try a recipe in it that has failed, not only because they are excellent, but because she is very specific in her directions and gives plenty of tips for beginners.
This chocolate egg white buttercream is one of my favorites because it's relatively simple (believe me, she's got some majorly complicated ones in that book) but extrememly delicious. I'd compare it to a light mousse. It's firm but airy and kind of dissolves on your tongue...sometimes it's like I'm eating rich chocolate air...but it does have substance so that's not exactly right. How about I let Rose do the talking...
"This special version of chocolate buttercream is the color of rich milk chocolate and has a more assertive chocolate flavor than the traditional one made with egg yolks. In fact, it is just as smooth and even easier and faster to prepare than Classic or Neoclassic Buttercream because a sugar syrup is not needed.
"This buttercream is airy yet, because of the whites' structure, has more body than a buttercream made with all yolks. It is an excellent texture and flavor for both chocolate butter cakes and chocolate genoise."
Thanks Rose, that about sums it up. Except I like it on any chocolate cake, any yellow cake, or white cake. I just like it period. It is NOT your typical frosting and I've found that frosting haters (the women in my family) usually enjoy this one, along with everyone else that is normal (frosting lovers).
Classic Egg White Chocolate Buttercream
Makes 4 3/4 Cups, enough to fill & frost a two layer cake
10 oz bittersweet chocolate (I always use semi-sweet chocolate chips)
2 cups (4 sticks) unsalted butter (must be room temperature)
4 large egg whites (must be room temperature)
1 cup granulated sugar
Melt the chocolate using a double boiler or in the microwave. I use the microwave & stir ever 15 seconds (after an initial 30 seconds). This time I accidentally did 45 seconds initially and that caused enough heat for the chips to completely melt as I stirred them. Do not overheat or the chocolate will seize up & you'll have to start over. Once melted, set aside to cool completely.
Beat the butter until smooth & creamy & set aside.
In another mixing bowl, beat the egg whites until soft peaks form when the beater is raised. (Veronica's note: if you're using the same beaters you used to beat the butter, wash them thoroughly before using them on the egg whites or they won't ever fluff up or get stiff. Fat is the enemy when it comes to beating egg whites!) Gradually beat in the sugar until stiff peaks form when the beater is raised slowly. Beat in the butter by the tablespoon. If the mixture looks slightly curdled, increase the speed a little and beat until smooth before continuing to add more butter (In my experience, sometimes the curdled look won't go away until all the butter has been added). Add the melted and cooled chocolate all at once and beat until smooth and uniform in color. Use immediately or place in an airtight bowl. Rebeat to restore texture.
You can store it 3 days at room temp, 2 weeks refrigerated, or six months frozen.
*Note : While it is necessary to cook egg yolks for a buttercream to prevent bacterial growth, raw egg whites are far less prone to this problem.
*Veronica's note: I know people are seriously paranoid about raw eggs, but I've made this a lot and can promise you that no one has gotten sick off of it yet--even after more than three days at room temp. I know, I live on the edge.