Minggu, 31 Agustus 2014

Vanilla Swiss Roll (香草瑞士蛋糕卷)

There're a few common problems with making Swiss rolls: (1) The cake is hard and dry. (2) The crust sticks to the paper the cake is wrapped in. (3) The crust cracks when you roll the cake.

Good Swiss roll starts with, of course, a sheet cake that's fluffy. You know what's wrong with a lot of Swiss roll recipes? They have way too much flour.

A cake that's 1-2 cm tall should have very little flour because it doesn't need much structural support. If it has as much flour as a cake that's 5-7 cm tall, it would be dense and hard.

There's no point in baking a cake that's fluffy but dried out. What makes my cake moist? Oil. It has more oil than flour. If you're on a low-carb, high-fat diet, this is the cake for you!

Water doesn't help make a sheet cake moist. Why? Because the cake is so thin, H2O in the batter evaporates very quickly. It's gotta be fat that keeps the cake moist. 

Of course, don't overbake the cake or it'll be dry no matter how much fat it has. Timing is critical because a 1-2 cm thick cake may overbake in 1-2 minutes. Make sure the cake is removed from the oven once the middle is springy when pressed lightly.

How to stop the crust from sticking to the paper it's wrapped in? Easy. Just don't wrap the cake in paper.

A lot of Swiss roll recipes tell you to roll the cake whilst it's piping hot, when it's most flexible and least likely to crack. This (the rolling, not telling) is done after placing the cake on a piece of parchment paper, and then dusting the crust with icing sugar.

The cake is rolled along with the paper, which stops the cake from sticking to itself.

The sugar is supposed to stop the crust from sticking to the paper, in theory. In practice, however, it doesn't because the cake releases moisture as it cools down. The paper traps the moisture that makes the crust wet and, hence, sticky.

How about wrapping the cake in a tea towel which breathes better than parchment paper? That works if the cake is quite dry when it's removed from the oven. But who wants a dried out Swiss roll, right? If it's moist as it should be, it'd still stick to the tea towel.

I let my sheet cake cool down on a wire rack after it's baked, without rolling or covering it.

Is my cake dry after it's cooled down? Not at all, because it has loads of fat and it's not overbaked.

Does my cake crack when I roll it after it's cooled down?

Nope, it doesn't because it's very flexible. The cake can stretch and bend into a roll without breaking. The flexibility is due to the way the eggs are beaten. The whites are whisked to firm peak stage, then the yolks are added one at a time and whisked thoroughly. Compared to the whole egg or chiffon method, this makes a cake that's more stretchable.

Some people wrap their Swiss roll, after rolling, to set the shape. If you want to do that, I suggest you use a tea towel. Parchment paper, if tightly wrapped around the cake for a few hours, will stick to the crust.

I prefer not to wrap the cake. There's really no need to do so provided the filling is firm when I'm rolling the cake.

If you use dairy cream filling, it must be firm when you're spreading it on the cake. And you must work quickly so it's still firm when you roll the cake. If it isn't, put the cake in the freezer for five minutes or so.

Here's how I make a Swiss roll (without pushing him down a mountain):



VANILLA SWISS ROLL (香草瑞士蛋糕卷)
(Recipe for one 13" roll)
Cake
140 g egg whites
60 g castor sugar
60 g egg yolks
40 g cake flour
1/16 tsp fine salt
1 tsp vanilla extract
60 g corn oil

butter for greasing pan
Filling
80 g chocolate spread
      or
215 g whipped cream (click here for recipe)
1 can (312 g) mandarin orange, drained and chilled

Image This recipe is double the pygmy-sized cake in the video.

1. To make cake, preheat oven to 200°C. Measure and prep ingredients as detailed above. Grease 13" x 10" pan with butter. Line pan with 13" x 13" parchment paper.

2. Whisk egg whites on medium-slow speed till thick foam forms. Gradually add castor sugar whilst continuing to whisk. Keep whisking till egg whites are at soft peak stage. Reduce speed to slow and continue to whisk till firm peak stage (when whisk is lifted, egg whites form peak that's hooked).

3. Add yolks to whites in 4 batches. Whisk on slow speed till evenly mixed after each addition. Sift half of cake flour into mixture. Add salt. Mix with whisk till almost even. Sift remaining cake flour into mixture. Mix with whisk till just even. Add vanilla extract and corn oil. Fold with spatula till just evenly mixed, banging mixing bowl against worktop 2-3 times.

4. Pour batter into cake pan. Spread with spatula as evenly as possible, pushing batter into corners of pan. Jiggle till batter is level. Tap pan against worktop twice. Bake on middle shelf till middle of cake is springy when pressed, 10-11 minutes. Remove from oven. Drop pan from 1' high 3-4 times. Unmould cake onto wire rack. Peel parchment paper from sides of cake. Leave till cool.

5. To assemble, place cake on new sheet of parchment paper, face down. Peel parchment paper from bottom of cake. Spread evenly with chocolate spread or whipped cream. Place mandarin orange, if using, in middle of cake. Roll cake as shown in video.

6. To cut chocolate spread Swiss roll neatly, dip serrated knife in hot water before each cut and wipe dry/clean with paper towel. For orange and cream Swiss roll, chill till cream filling is set, then use a serrated knife that's wiped clean after each cut.

7. Orange and cream Swiss roll is best eaten after an overnight rest in the fridge, when the filling has had time to perfume the cake. Chocolate spread Swiss roll should be chilled or eaten once it's made. Otherwise, oil separates from the spread and seeps into the cake, making it hard.