Joining the Daring Bakers has really been fun, in that it gives me the opportunity to use skills I learned in culinary school that I would never otherwise use at home. With this stuff it's use it or lose it - and it doesn't take long as I've discovered!
This months' challenge was a "Strawberry Mirror Cake" a classic French patisserie concoction involving a sponge cake layered with Bavarian Cream and topped with a clear strawberry gelatin layer - a.k.a. the mirror. We actually did a Passionfruit mirror cake in my cake decorating class last semester, (at Grossmont Culinary School, taught by James Foran - the pastry chef at Market.) Unfortunately the cake had to chill for several hours in order to firm the filling, so the mirror had to wait for the following class - when I was absent. Not only did I not get to see the mirror, but since I wasn't there when the cake was finished, I didn't get to take any home! Poor, sad me.
The cake we prepared in class was somewhat different from this recipe. We lined a ring mold with a thin layer of joconde sponge, patterned with a chocolate tuile batter. The mousse was the poured inside, allowed to firm, and then covered with the mirror. It was an elaborate process - but not especially difficult, technically.
For the lining (I wish I had a picture of the other side!) we laid a patterned template on a silpat with holes punched in it - stripes, checkerboard or polka dots, and spread the chocolate tuile batter over the form. It was then lifted off, leaving the pattern on the silpat. Sponge cake batter was spread on top of that (carefully) and then baked. The patterned cake was then cut into strips for lining the pan. (If you look at the cake in the bottom right of this photo, you can see how it looked before the mousse was added.)
For the July challenge, Peabody's method called for us Daring Bakers to make a layer of sponge cake in a jelly-roll or sheet pan, cut the layers to fit a springform pan, and cover it with Strawberry Bavarian Cream - sort of a firm mousse - then with the mirror. The rules specified that the cake had to be white, but substitutions were allowed for the fruit and the gelatin if anyone was allergic or averse to gelatin. As far as decorating, the only rule was that you had to be able to see the mirror.
This was a fitting send-off to the local summer strawberry season, and I picked up a couple of boxes at the Farmers' Market last Sunday that I used for the puree and the juice. I made those earlier in the week and stored them in the fridge until I was able to get around to the cake itself on Saturday. (The cake needs to chill for several hours in order to let the fillings firm up, so it's not a bad idea to make the fruit puree and juice and the cake ahead of time.)
The sponge layers came out nice and airy and were brushed with a simple syrup spiked with kirsch for flavor. With this type of cake it's important to really beat the heck out of the sugar and eggs at the beginning to get them to full volume and give the cake a nice elastic base. The cake flour is sifted into the sugar and egg mixture, and then a meringue is folded in for lift. The key is to not stir too much, or the batter will deflate. My layers came out about 3/4 of an inch thick.
As I prepped it, I realized the Bavarian Cream has all the ingredients for strawberry ice cream - just jelled instead of frozen. You start with a custard - cooking egg yolks, sugar and milk together until thickened. The strawberry puree and gelatin are stirred together and added to the hot custard, and after the custard mixture is cooled over an ice water bath, softly whipped cream is folded in. (I had to add a couple of drops of red food coloring for the pink color, since the cooked cream had an unappetizing slightly grayish color.)
One thing I was a little confused about - the recipe seemed to call for 2 1/2 Tablespoons of gelatin (noted in the recipe as TBSP) - but a packet of gelatin contains 2 1/2 teaspoons of gelatin. I wasn't sure, but I figured two packets ought to do it (close to 2 Tablespoons altogether.) That seemed to work fine, but I am curious to see if other people used different amounts, and what their results were.
I added some cut strawberries to the sides of my cake - both for decoration and because I cut my cake layers a little on the small side (I used the pan as a guide, but I guess I overdid it on the trimming!) I placed them against the sides of the pan before adding the cream, then added the second layer of cake, and filled it in with the cream - being careful to leave space for the mirror.
I lined my pan with parchment paper, thinking it might help keep the strawberries in place when the sides of the pan were removed. The paper absorbed moisture though, and sort of crinkled a bit - I wouldn't bother with that the next time.
When the cream was thoroughly chilled and firm, I made the mirror topping. Again, this seemed to call for a large amount of gelatin - 1 TBSP. I used one packet (2 1/2 teaspoons) which seemed to work well. I added the fruit to the top before putting the cake in the refrigerator to firm.
I was really pleased with the way the cake looked when I unmolded it, even if it was a little crinkly. I was planning to take it to a barbeque yesterday to share it, but unfortunately we weren't able to go. (Sorry Mendy - and Happy Birthday!) It doesn't keep well out of the fridge, so taking it to work is out. Husband is at work tonight... hmmm... Guess I know what I'm having for dinner!