Matcha Swiss Roll

Knock, knock!

Who's there?

Matcha!

Matcha who?

Much ado about Swiss rolls.

This is another Swiss roll post, the third on this blog. 

My matcha sheet cake is barely sweet, to keep it in character with green tea which is drunk without sugar. It has quite little oil because matcha doesn't absorb much oil. My vanilla sheet cake, in comparison, has twice as much. Green tea powder also helps "lighten" the cake. You know how tea makes food seem less rich? Matcha does that with cake.

If you don't know much about matcha, please read my post on matcha layer cake. You'll find information on what type of matcha to buy and how to store it. 

My matcha sheet cake uses the chiffon method. Making the batter is quite easy. Just do the usual stuff that applies to all cakes, e.g. measuring the ingredients correctly, not over- or underbeating, not over- or undermixing, etc.

The baking part is less straightforward. When I bake the cake, I block the oven's bottom heat around two-thirds of the way. Why? To keep the inside of the cake moist whilst allowing the crust to dry out sufficiently. Without blocking the bottom heat, the crust would be sticky when the inside is just right. And if the bottom heat is blocked too early, the bottom of the cake would stick to the parchment paper.

What makes the crust dry out slowly? Matcha. Some of the fine powder rises to the top of the cake when heated. Do wet leaves dry well in the oven? No, not as well as flour which has starch to help it set. That's why the crust needs the tray's help.

I like to fill my matcha roll with matcha whipped cream and red beans. You can, of course, make sweetened red beans from scratch. But chances are your homemade version won't be as fragrant as Japanese canned red beans unless your beans are from Hokkaido. Chinese red beans are far inferior.

I've tried two brands of red beans: Hashimoto and Imuraya. Both are fragrant but I prefer Hashimoto. It has more bite and is less sweet.

Imuraya beans are mushy and the syrup, because it's thickened with cornstarch, is very gloopy. The gloop clings to the beans, adding to the sweetness and mushiness. Unlike Imuraya, Hashimoto is thickened with sorbitol. The syrup isn't as thick at room temperature, so I can drain it.

One small can of Hashimoto, 190 g, yields 130 g after it's drained. Leftovers may be refrigerated for a few weeks or frozen for a few months.

I like my matcha roll "naked", i.e. it's rolled inside out and there's no icing. I think the green, spongy look is quite pretty. Is rolling the cake difficult? Not at all. The cake handles well (provided it's made right). If you don't know much about rolling Swiss rolls,

After you make the Swiss roll, have a small piece to see what it's like. Take note of the taste and remember it. Keep the rest of the roll in the fridge, covered, for two days. Your saintly patience will be rewarded with a matcha flavour that's more intense than two days prior, and melded with the red beans. After taking a bite, you'll never again eat matcha Swiss roll that's freshly made . . . or store-bought.

Here's my video to walk you through the recipe:

MATCHA SWISS ROLL  (Recipe for one roll) Cake 10 g water  1/2 tbsp green tea powder 30 g egg yolks 10 g castor sugar 25 g corn oil 35 g cake flour 80 g egg whites 1/4 tsp cream of tartar 30 g castor sugar Filling 75 g fresh dairy cream, 35% fat 1/2 tsp green tea powder 40 g red beans 1. To make cake, preheat oven to 170°C. Grease 12" x 9" cake pan with butter. Line with parchment paper. 2. Add water to green tea powder. Stir till smooth. 3. Whisk egg yolks with castor sugar till thick and pale. Add corn oil. Whisk till thick. Add green tea paste. Mix till even. Sift cake flour into mixture in 2 batches. Mix till just even after each batch. 4. Whisk egg whites till very frothy. Add cream of tartar. Whisk till thick foam forms. Gradually add castor sugar whilst continuing to whisk. Keep whisking till firm peak stage. 5. Add egg whites to yolk batter in 2 batches. Mix with whisk till almost even after each batch. Scrape down and fold with spatula till just evenly mixed, banging bowl against worktop 2-3 times. 6. Scrape batter into cake pan. Spread as evenly as possible. Jiggle till batter is level, banging cake pan against worktop 2-3 times. 7. Bake till cake is springy, about 20 minutes. 8. Remove pan from oven. Drop from 1' high 2-3 times. Loosen cake with knife. Drag onto wire rack. Leave till cold. Remove from wire rack. Place new parchment paper on cake. Flip cake upside down. Peel old parchment paper from cake, slowly. Flip again. 9. To make filling, whip cream till thick enough to hold its shape. Add green tea powder. Whisk till thick enough to stick to whisk. 10. To assemble Swiss roll, spread cake with whipped cream, then red beans. Roll. Refrigerate for 2 days, covered. Remove from fridge. Cut with serrated knife, wiping knife clean after each cut. Tuck in when cake is soft but filling is still firm.