Wednesday, August 19, 2009

Experiment #1: Results and Discussion/Conclusion

There were a lot of steps involved with making this entire cake and I’ve learned a lot from this experiment. Here’s the play-by-play breakdown on each step:

Part 1: Making the génoise cake
Not to intimate anyone into making this cake, but even the fist task of lining the pan with parchment paper is not as easy as it seems in the instructions; it actually required some math! First I traced the bottom of the pan on the parchment paper (pencil works well) and cutting out the piece to fit the bottom. For the sides, cut a 2-3” wide strip (the cake doesn’t rise all the way to the top so it doesn’t have to be perfect) of parchment and as long as the circumference of the pan. How long is that? Well, 2πr long. Or 2*3.14 * the radius of your pan (5” for my 10” diameter pan). So I cut a piece that was 31” long. Is this lesson in geometry a bit excessive for a stupid pan lining? Yeah, but at least you won’t waste your parchment paper. :P I found that it was easiest to line the sides first with parchment paper, then slide in the bottom piece so that it “holds” the sides in.

The prep work for the cake wasn’t too hard at first; after all, I’ve made cake batters before. But then I tried the folding of the flour into the batter and lo-and-behold, the flour sinking to the bottom, just as Elizabeth had warned. I thought I had my eye on the flour, but as I was pouring out the batter, I found a significant amount of flour at the bottom so I had to quickly blend in the flour at the last minute. The result: lumps in my batter. I definitely need some work practicing folding in flour for this cake before I can call up Tartine for a try-out.

Part 2: Making the pastry cream
I discovered a trick early on in the process of making the pastry cream. My vanilla beans were very stiff and I could not slice it in half without cracking the whole thing. I first contemplated adding the hard chunks of vanilla bean, pod and all, into the milk, but came up with a better idea: microwave it! Twenty seconds and the bean was soft and sliceable again. The most challenging part was the addition of the hot milk to the egg/sugar mixture while whisking; this required the ability to do two different actions with your hands (kind of like patting your head with one hand and rubbing your belly with the other). I ended up whisking with my left hand and pouring with my right hand, which was probably not the best way to do it since I am right-handed. Next time, I will set up the egg/sugar bowl to the right of my burners, so that I can pour the hot milk from the left and whisk with my dominant right hand. I also found that the cream didn’t flow very quickly through the sieve. At all. So I used my spoon to smoosh it through. Not elegant, but it works.

In the end, the pastry cream ended up much thicker than I imagined; it was the consistency of a thick pudding after it cooled (I could make plenty of polymer references to describe the consistency, but there’s definitely no comparison in taste!). I stirred it occasionally while I got ready to assemble the cake.

Part 3: Making the filling and assembling the cake
Elizabeth instructs us to line just the inside rim of the pan with plastic wrap and not the bottom. When I read this, I was puzzled on how to achieve this. So with a little experimentation, I found this way worked for me: take two large sheets of plastic wrap and stick them together along the long side. Then put the bottom of the pan on top of the wrap, and wrap the plastic wrap into the middle of the pan. Then I placed the outside rim of the pan around the plastic wrapped bottom. Once the rim of the pan is attached, unfold the plastic wrap and pull it back so that it covers the sides and hangs over the rim of the pan. Voila!

To cut the cake evenly, I found myself placing my hand on top to gauge the evenness of the cut. I also stooped down to counter-level so that I could see the cutting process. I sawed gently all the way around first to mark where I would cut, then I cut deeper the second time around. That worked pretty well and cake came out fairly even!

In my preparation to make the filling, I was intrigued about the role of gelatin; I had never used it in my baking before. What was this stuff going to do to the pastry cream that I had just made? I was amazed that the stuff absorbed all of the water I added almost immediately to form what we would call in lab a “gel.” I wondered how adding this gelly-blob to the pastry cream would work, and I was amazed that when whisked into the hot pastry cream, it “melted” to form a smooth cream product. (At my job, we don’t want our gels to melt like that!) Honestly, the cream looked the same before and after the gelatin. But I think if I were to compare cooled plain pastry cream and pastry cream with gelatin, I would notice that the one with gelatin was more firm since macromolecules such as gelatin will have different physical properties at lower temperatures. I’m imagining the protein structure of gelatin freezing up when it is cooled, trapping the pastry cream in its network. The result is a sliceable cream filling.

When I took the cake out of the fridge to top it with the whipped cream, the assembled cake reminded me much of a giant ice cream sandwich. The filling peaking out on sides of the cake wasn’t perfectly smooth and I realize now that I should have put more pressure to even out the filling when I originally assembled the cake. Oh well, I’ll have to improvise. Since I didn’t have any more strawberries left, I sliced some nectarines thinly and lined them along the side of the cake. The cake didn’t look like the one in the book, but it still looked good to eat!

I added the whip cream topping next and being the perfectionist that I am, I kept smoothing the top, and eventually it started to look “grainy.” Adding more whipped cream didn’t help either; I think there is a certain window of time that one can manipulate the whip cream before the “graininess” sets in. Lesson learned; plop the whipped topping down, smooth over once or twice then leave it alone.

Too much manipulation of whip cream :(


This by no means is an easy cake to make, but with a little determination and a big sweet tooth, it can be done in about 2.5-3 hours. Overall, the taste of my cake was successful (though I’ve never tasted the real thing); it was creamy, not too sweet and the cake base was scrumptious (so my friend C.H. said!) The co-workers devoured it and I’ve probably gained a pound or two from it, but it was well worth the experience. In future repeats of this experiment, I hope to address the key mistakes I made, which will hopefully improve the aesthetic quality of the cake:

*Genoise cake: when adding the flour to the batter, REALLY dig to the bottom of the bowl to scoop up the flour and to ensure good mixing.

*Pastry cream: work with the egg/sugar mixture on the right-hand side (if you’re right-handed like me); pour milk with the left hand, whisk with the right.

*Cake assembly: I would probably put more syrup on the cut-side of the top of the cake so that it would have been a bit sweeter. Also, press the top of the cake firmly to make sure filling will be smooth on the sides of the cake and don’t mess around with the whip cream topping too much or it’ll look ugly. Still tastes good though!

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