Yammy Swiss Roll

I think I have fallen in love with Swiss rolls these days, thanks to my friend for the trusty Swiss roll book that she has given me - 孟老师的美味蛋糕卷. It can be a challenge finding dependable baking books. Most books seem to scrimp on details when it comes to instructions and they would rather focus on quality styled food photography. This phenomenon seems to be more noticeable in asian bakebooks, where many a times I have spotted missing instructions, missing ingredients, blatantly wrong oven temperatures and the list goes on. Sometimes I wonder... Do the editors and authors ever bother to proof-read their work? There is no doubt that the recipes do work but I wished that more attention is paid to details.

In many aspects, this book puts many other authors to shame. The book starts off by informing the reader the conversions for the recipes when using different pan sizes. Subsequently, the author illustrates the making of 5 different kinds of sheet cakes with step-by-step photos. Next, she goes on to explain the preparation of different fillings, methods on rolling sheet cakes and introduces the required equipment and ingredients. The book comes with an instructional DVD which I have yet to use. Even without the guide of the DVD, I am able to follow her recipes and instructions with ease. If you are thinking of getting a book on Swiss rolls, you know which book to pick best.

This yam Swiss roll is the third recipe I am using from the same book. Previously, my yam Swiss roll broke while rolling as the sheet cake was too moist and it stuck to the baking paper. Hence, I have reduced the liquid contents this time. If you noticed, my swiss roll looks flat at the top. After I made my Swiss roll, I wrapped it up in baking paper and chilled it. I was unaware that my swiss roll was positioned upside-down, hence resulting in the flat top. I learnt something new again this time; remember to rest your Swiss roll upright. 

Having tried two methods of cooking the yam - steaming and boiling, I find that it is more desirable to steam the yam as it produces a nicer flavour. When the yam is boiled, some of the flavour and nutrients are lost to the water. However, it takes nearly an hour or longer to steam the yam while it takes only 15-20 minutes to boil the yam till it is soft enough to mash. 

*Yam is known as Taro in some countries and in America, sweet potatoes are known as yam.

Yam Swiss Roll (Recipe adapted from 孟老师的美味蛋糕卷)

Serving size: 8 to 10 slices
Taste and texture: Cake base is soft, moist and fluffy. Yam paste is smooth and carries a coconut fragrance.
Equipment and materials:
1) 12 x 12 inch pan or 10 x 14 inch pan
2) Stand electric beater/ handheld electric beater
3) Spatula
4) Wire whisk/balloon whisk
5) Mixing bowls
6) Wire rack
7) Flour sieve
8) Parchment/baking paper
9) Brush for oiling pan
10) Weighing scale

Chiffon Cake Ingredients:
80g egg yolks, room temperature
25g castor sugar
2tbs + 1 tsp corn oil
2tbs + 1 tsp water or milk
75g cake flour
160g egg whites
60g castor sugar

Yam Paste:
275g yam
45g icing sugar
35g unsalted butter
3 tbs coconut milk

Making the yam paste:
Peel yam. Do not wash the yam. Cut the yam into small strips and steam on high heat for about 1 hour or until yam is very soft. Smash yam with two fork and mix well with icing sugar. Add in unsalted butter to combine. Lastly stir in the coconut milk and mix well. Yam paste should be smooth.

Making the chiffon sponge:
Prepare Oven and line pan - Preheat oven to 180 degrees C and line tin with baking/parchment paper.

Preparing the egg yolk mixture - In a large mixing bowl, whisk together the egg yolks, 25g castor sugar, vegetable oil and water until combined. Sift in cake flour to egg yolk mixture and mix until smooth and well combined.

Beating egg whites - In a metal bowl, beat eggs whites starting with low speed. When the egg whites turn frothy, slowly increase the speed to high and beat until egg whites are soft peaks (egg whites form peak that is drooping). Add the sugar (60g) slowly at this point and continue beating until egg whites are nearly stiff but still moist and not dry. This is when the bowl is overturned, the egg whites would not budge. Egg whites will form shiny and creamy upright peaks when beater is withdrawn. Take care not to overbeat the egg whites as they will become dry or may water out.

Folding egg whites into egg yolk mixture - Fold one third of beaten egg whites with a balloon whisk into egg yolk mixture to lighten and mix well. Incorporate another one third of the whites. Lastly, add the rest of the egg whites and fold gently to obtain a smooth uniformly coloured foamy batter. Scrape sides and bottom of bowl with a spatula to ensure batter is well mixed.

Baking the cake - Pour batter into a 12 x 12 inch tin or 10 x 14 inch lined swiss roll tin. Level the batter and bake for 8 - 11 minutes. Start checking for doneness at 8 mins. Cake is done when inserted toothpick comes out clean. Allow sheet cake to cool.

Assembly:
Turning the cake out - Carefully turn the baked sheet cake onto a piece of baking/parchment paper. Slowly peel off the attached baking/parchment paper from the cake. Place a new piece of baking/parchment paper over the sponge. Invert the sponge again, carefully. Now, peel of the top piece of baking/parchment paper. The skin would be stuck to the baking/parchment paper and would be removed.

Rolling the cake - Make a few slits across the breadth of the cake at the side nearest to you with a knife. Apply yam paste evenly over the surface of the sheet cake. With the shorter side/breadth facing you (if using 10 x 14 inch pan), roll the cake up tightly to form a swiss roll. Trim both ends to get a presentable looking swiss roll.

Notes:
1) If sheet cake is too moist after baking and cooling, return it to the oven and bake it for a further 2-3 mins at 180 degrees C.
2) The icing sugar and butter is best combined with the yam when it is still hot.

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