Mirror Glaze

I had a vague idea of what I wanted my next cake to look like and randomly Googled some terms I thought I had invented.  A whole world of mirror glaze opened up before me.

Mirror glaze is basically gelatinized white chocolate ganache.  You color it, get it to a precise temperature, and pour it over a frozen cake, where the gelatin sets almost immediately in a unique swirl.

You're supposed to use this glaze on an entremet cake, which is a project.  You fill a cake mold partway with mousse, set the cake on it, fill in the sides with more mousse, and freeze the whole shebang.  Once it's unmolded and trimmed even, you glaze it.  You can also do this with a buttercream-frosted cake or a pre-baked cheesecake that hasn't cracked.  Just make sure the icing is as perfect as you can get it and the cake is frozen for at least 8 hours.  Otherwise, all your frosting is going to melt right off.

All of the recipes I researched weren't exactly snobby with the "use real white chocolate" mantra so much as stressing the importance of there being actual cocoa butter in the glaze.  Most "white chips" are palm kernel oil.  I presume it has a different melting point than cocoa butter and won't firm up correctly when the gelatin does.  I got lucky and went to Smart&Final the day Ghirardelli bars were on sale for $2.49 for 4 oz.  If I'd known how much glaze this made, I could have made a half-recipe for the 6" cake and saved a bit.  This cake project is picking at my grocery budget bit by bit.

This recipe is from Southern Fatty.  It worked the way I wanted it to, so that's what I'm posting.  Because this concept is almost a chemistry project, recipes aren't going to vary that much.  The one thing everyone agrees on is that the glaze must be between 86º and 90º F when you pour it, or the mousse/icing will melt before the glaze sets.  Any cooler, and it won't pour smoothly.  Also, pull the cake out of the freezer less than a minute before you start pouring.  Moisture starts to bead up on the surface of the cake almost immediately, which will also cause the glaze to slide off.

2 packets plain gelatin powder, softened in 1/3 C cold water
1/3 C + 1-1/2 Tb water
200g (about 1 C) sugar
2/3 C corn syrup
1/2 C sweetened condensed milk
200g chopped white chocolate (2 4-oz Ghirardelli bars minus 2 squares)

1.  In a medium saucepan over medium heat, bring second water, sugar, and corn syrup to a low boil. Stir to make sure everything is dissolved.  Don't go for a full rolling boil, or you'll start to make candy.

2.  Remove mixture from heat and stir in gelatin until dissolved.  Add condensed milk and pour over white chocolate.  Allow to sit for 5 minutes.

3.  Using an immersion blender, whiz the mixture until smooth.  Don't have one?  Neither do I.  What I did was soften the chocolate in the microwave before pouring the hot mixture over it, then stir for quite a while until I figured that was as good as it was going to get.  (See photo at top of post.)

4.  Run mixture through a strainer to catch any unmelted chocolate.  This was easier to clean than I expected it to be.  Between the gelatin, condensed milk, and white chocolate, the glaze is going to smell like feet.  The smell goes away when it's on the cake.

5.  Portion out glaze into bowls and color with gel or powders.  The recipe again suggested an immersion blender, but I had no trouble getting even colors with spoons.  Check temperature every few minutes by stirring with the thermometer.  When it gets down to 90º, get out the cake and start pouring.

Makes 3 C glaze, enough for a 10" cake

Difficulty rating  π