Matcha Sakura Petits Fours

The Art.

    One of my favorite things about my visit to Japan last fall was all the pastries. When I discovered that the entire ground floor of Daimaru department store was devoted to desserts, I almost refused to come back the US. This spring, I was reminiscing about our trip and thinking about how wonderful it would be to go back during sakura season. I decided to make little Japanese-inspired springtime petits fours to tide me over until I can visit again. Since I ran into matcha flavored EVERYTHING while we were there, I started out with matcha flavored cake and icing. I also discovered this amazing sakura blossom paste that is absolutely to die for, so I used that as the filling in the petits fours. Topping the cakes off with pink blossoms brings together the sakura blossom theme!

The Science.

    Matcha is a bright green tea that is made by shading tea plants before they are harvested. This causes the leaves to produce more green chlorophyll, so they can make more energy from the little sunlight they get. This method produces tea with a strong, distinctive flavor. One of the things I noticed while I was testing recipes was the difference in color and flavor between different matcha powders. I researched this a little bit, and came across an amazing thing I didn't know about: there are electronic intelligent instruments called the E-nose and E-tongue that detect odors and flavors! These instruments have "diverse sensors generating different signature phenomena to fully exploit the characteristics of test samples," and are paired with sophisticated computer algorithms to predict what a person would taste and smell from the tea [1]. In plain English, the E-nose and E-tongue can "smell" and "taste" the way humans do. Many food scientists have quantified the compounds that give matcha its distinct flavor by mass spectrometry [2,3], and the E-nose and E-tongue use this information to generate a flavor profile from the tea and give it a grade classification. This technology, in addition to being really cool, is used to eliminate the variation between human tasters and the influence of their taste preferences on the tea's classification. I just can't get over the fact that there are tea-tasting robots! Do they have tea parties?

The Recipe.

Matcha cake:
3 egg whites, divided
3/4 cup sugar, divided
1 cup cake flour
1 1/2 teaspoons baking powder
5 grams matcha powder 
1/3 cup salted butter 
1 teaspoon vanilla
2/3 cup buttermilk
Sakura paste (filling)

    Preheat oven to 350°F. Coat a 9x13 inch baking pan with baking spray, and line with parchment paper. Beat 2 egg whites and 1/4 cup sugar together on high speed until stiff peaks form. Set aside. Beat together butter, sugar, vanilla, and remaining egg white. In another bowl, combine flour, baking powder, and matcha. Alternately add one third of the flour mixture and buttermilk to the butter mixture, beating between each addition just until combined. Fold in beaten egg whites with a spatula. Spoon batter into pan and smooth the top with a spatula. Bake on center rack for 15 minutes, or until tester comes out clean. Cool 10 minutes in pan, then invert onto wire racks to cool completely.

Matcha poured fondant:
4oz Ghirardelli white bar chocolate 
5 grams matcha powder
6 cups powdered sugar
1/2 cup water
2 tablespoons light corn syrup

   Heat chocolate in a large microwave-safe bowl in 30-second bursts, stirring inbetween, until melted.  Add matcha. Stir in powdered sugar, 1 cup at a time, adding small amounts of water at intervals. Stir in corn syrup. Icing will be very thick. If desired, tint the icing a brighter green with gel icing colors.

Assembly:
    To make pretty petits fours, you must be very accurate while cutting your cake. First, level the top of the cake with either a cake leveler or a long serrated blade. Next, get out your ruler and cut your cake straight down the middle to create two 9x7.5 inch pieces.  Spread a thin layer of sakura paste on one side and top it with the second cake layer. Get your ruler out again, and cut your cake into one-inch strips. Carefully score the top of your cake strips into one-inch squares with your serrated knife, then very gently cut your petits fours with a slow sawing motion.
    To ice the petits fours, balance one cake on a fork over the bowl of poured fondant. Spoon fondant over the cake and then allow to dry on a wire rack. You may want to coat the petits fours once more to give them a nice smooth finish. Before the second layer dries, top with pink gum paste blossoms. Either pipe some icing into the flower center or add edible pearls to complete your cherry blossoms.
    Store petits fours in the fridge for up to one week, or freeze if storing longer.

References:

1. Zhi, R et al. "A Framework for the Multi-Level Fusion of Electronic Nose and Electronic Tongue for Tea Quality Assessment." Sensors (Basel). 2017 May 3;17(5). pii: E1007. doi: 10.3390/s17051007.

2. Wang, L.F. et al. "The Compounds Contributing to the Greenness of Green Tea." Journal of Food Science, 69: S301–S305. doi:10.1111/j.1365-2621.2004.tb09894.x

3. Lee, Lan-Sook et al. "Metabolomic Analysis of the Effect of Shade Treatment on the Nutritional and Sensory Qualities of Green Tea." J. Agric. Food Chem., 2013, 61 (2), pp 332–338

DOI: 10.1021/jf304161y