Sunday, May 15, 2011

RHC: Zach's La Bomba

Zach's La BombaAnd here it is, the last cake (barring the wedding cakes) from Rose's Heavenly Cakes: Zach's La Bomba. It's a pretty fitting finale to my 84 weeks of "cake-of-the-week" and sometimes "cakes-of-the-week", as it's one on the complicated end of the scale for Rose's cakes. Or un-cakes, because there's not much cake in this delectable dessert.

One part that seemed to be giving several HCB'ers difficulty was a snap for me: finding the black currant or blackberry tea. I've been drinking a lot of hot tea the last couple of years and always have at least 4 or 5 varieties around, and among the current collection is some Twinings Blackcurrant Breeze. If I'd thought of it earlier, I'd have been glad to send a bag to those who were searching everywhere for the stuff, as I'm not that fond of it as a drinking tea.

The La Bomba has three parts: a very thin flourless chocolate cake base, a chocolate and blackberry mousse filling, and the chocolate "lacquer glaze" that produces a mirror finish...if it comes out. The lacquer glaze is used 4 times in RHC, though I skipped it on the Bernachon Palet d'Or and used the leftover from the Chocolate Apricot Ginger Roll with Lacquer Glaze to do the Designer Chocolate Baby Grands. If you were counting, that means this was only my second attempt at the glaze.

Zach's La BombaFirst up was the cake, which was pretty straightforward after all these weeks of developing skills like beating egg yolks and sugar until the mixture falls in ribbons, making a meringue, and folding it all together with melted chocolate. My cake did look bumpy on top and had several domes as it came out of the oven--rather like a lunar landscape effect, actually--which subsided as it cooled. It also seems like it should have been possible to cut the recipe down and bake in a smaller pan, for you only need about a 6- or 7-inch circle of cake from the half-sheet pan. As I do have extra, I'll take Rose's advice and use the trimmings for a quick trifle with some fresh berries. It has a very nice chocolate flavor.

I got the cake baked, trimmed and into the freezer a week or so early, and that's about all you can do in advance unless you choose to make the glaze early and re-heat it when needed. All the mousse components must be done in one run, one which took me 3-1/2 hours from when I started measuring ingredients to when the bombe went into the freezer. And as Marie said, you can use up most of your bowls and your counter space in the process.

The mousse has five components itself: a tea sabayon, two ganaches, blackberry puree, and whipped cream. (You can combine these in various ways and say it was only three components or even just two, but I think of "things that got stirred up in their own mixing bowl", and come up with five.) The sabayon is a mixture of egg yolks, sugar, and the blackcurrant tea whisked together over simmering water until it reaches 170 degrees. Rose says "5 minutes", but just like all the custards and such in this book, my sabayon took much longer than the recipe said--more like 20 or 25 minutes. Ganache #1 went into the sabayon when it was at temperature, then that blend went into an ice-water bath to cool down (count another large bowl for the ice-water).

Zach's La BombaThen came the blackberry puree, quickly produced by the Cuisinart food processor, then strained. I made the straining easier on myself by using more blackberries than called for, so I got the needed 1/2 cup of strained blackberries without a lot of scraping and pushing through the sieve. Gelatin was incorporated into the puree and that was then set aside. Then came ganache #2 which broke on me--but I dipped into the remaining cream to pull it back together. Then the ganache had to cool to room temperature.

Zach's La BombaAt this point I had a sink full of dirty utensils, and three bowls of good stuff: the sabayon+ganache, the blackberry puree with the gelatin, and the second ganache. Time to put it all together: whip the remaining cream, add ganache #2, fold in the blackberry puree, and fold in the sabayon. Put it all in the silicon bombe mold I bought a few years ago, pop the cake circle on top, and....I discovered the cake circle was too large. I had cut it to fit the top of my mold, but the mousse was an inch or so below the rim. After a hurried trimming I was able to get the cake circle pressed onto the surface of the mousse and get the whole thing into the freezer. After that? An hour or so cleaning up the mess I'd made of my kitchen.Zach's La Bomba

Zach's La BombaA day or so later the mousse was solidly frozen and I was ready to finish off the La Bomba. Making the laquer glaze went smoother than my first attempt, but it took a lot longer to cool to the ideal 80 degrees for coating the bombe than I expected. OK, I gave up at 83 degrees, as I needed to defrost this thing so I could slice it the same evening--I left town Friday morning and came back Sunday night, not leaving time for cake preparation before the Monday posting date. I think I had the glaze too cool the first time I used it back on the cake roll, and from my results this time a little too warm is better than too cool.

Zach's La BombaWhile waiting for the glaze to cool I unmolded the bombe. The silicon mold behaved fairly well...or maybe I should say that I managed fairly well with the unmolding, this being the sort of skill I don't do well with in general. I pulled away at the edges a bit to loosen, then ended up with a double-handed, thumbs on the bottom, gentle push to get it out. That operation left one sort of dimple in the side of the bombe, easily smoothed out with a spatula. Zach's La BombaI poured over the glaze and it went on like a dream. I moved the bombe over to a serving platter, then found the bottom (formerly the top) wasn't flat--apparently my trimming of the cake round didn't get it quite flat, and so my beautiful glazing job was held a little in the air above the serving plate on one side. I didn't take pictures of that side. :)

On serving I found that my cake round also didn't adhere to the mousse, as it popped off each slice as I turned them onto individual plates. Perhaps that will improved as the bombe sits in the fridge...or not. When I served a second round to the nieces this evening the base was still falling off at every opportunity.

DSCN2780Tasting comments: The bombe is a very light chocolate mousse, the melt away in your mouth sort. I get very little contribution from the blackberry and black current additions, perhaps overwhelmed by the chocolate in the mousse, the chocolate glaze, and the chocolate cake base. The very thin cake base really doesn't do much for me at all--it's too thin to contribute much to the taste, and mostly functions to make it easier to handle the bombe. I think I'd skip it on a repeat and serve the mousse by itself, maybe with the glaze or another dark chocolate sauce as an accent.

Overall I primarily taste chocolate, with maybe a hint of berry. The nieces and my older brother agreed--mostly chocolate, maybe a little bit of berry flavor. Everyone liked it, though younger niece would prefer hers frozen--when I cut it Thursday for our first tasting it hadn't completely defrosted. She put her second piece into the freezer tonight.

So, that's it: 95 or so cakes, depending on how you count 'em. 20 months. I'll post a summary in a bit, and may poll the family and the folks at work for their 'best' cakes now that I'm done.Zach's La Bomba


  1. Congratulations! I think our experiences with this cake were very similar. I also got impatient several times and fudged (no pun intended) on the temperatures a couple of times.
    Who would ever think that your black currant tea would turn out to be so valuable in the cake market?

  2. Wow, no wonder I keep waiting for a day to myself to make the sabayon! Your bombe looks perfect. Maybe the brand of chocolate you used canceled out the blackberry flavor? I look forward to your post-bake-through thoughts and the possible poll.

  3. Nancy - What a great post. I am getting ready to finally make this LaBomba and your words have helped me so much. I have been eyeing all the contortions with a jaundiced eye, but you have really sorted it out well for me. Thanks. Joan

  4. Joan--

    Glad it helped you out. I found it interesting to come back and read the post 10 months later, and remember all those mixing bowls. :)