one thing leads to others. Luca is made of white chocolate, so i decided to decorate his birthday cake with the best white chocolate buttercream i know of: the white chocolate lemon buttercream; from ROSE’S heavenly CAKES: Woody’s Lemon Luxury Layer Cake (page 409). i omitted the lemon curd.
it turned out shapely and perfectly smooth. also, it cake survived a 45 minute airplane ride and been kept at room temperature till the next morning (74 oF).
2 secrets of success: measure the correct amount of yolks. measure by weigh: yolks and whites separately. depending on what part of the world you live at, yolk size varies tremendously. for my hens, yolks come small, so i add one extra yolk per 8 whole eggs, then subtract whites till i have the total grams needed on the recipe. this buttercream recipe calls for 4 whole eggs, and i made a 2x recipe, so for 8 whole eggs I used 9 yolks and the rest in whites. please look at a cake recipe calling for yolks and/or whites separately to determine the weight of one yolk and of one white.
the next secret of success is to use an accurate digital thermometer. white chocolate is VERY temperature sensitive. egg yolk curdling, too. i promise with all i can give and take: if you have a good thermometer and follow all the temperatures indicated on this buttercream recipe: you will achieve heaven (a non-curdled heaven!).