Matcha Mousse Tart

I can't stop dreaming about Japanese matcha desserts.  In case you're not familiar with matcha, it's a ground green tea in powder form, and it's one of the most brightly colored teas you'll ever see.  I bought some from Ippodo at their main store on Kyoto's Teramachi Street, and I brought it home with me to Virginia.  I plan to make as many matcha sweets as possible before its expiration date.  This mousse tart takes a little bit of time, but it's light, airy, and earthy.  Oh, and it's a magnificent shade of green.

While in Kyoto, I sampled a very wide variety of matcha desserts, and aside from the ice cream, a slice of a matcha mousse tart was my favorite.  It turns out it's difficult to find a good recipe in English.  Thanks goodness for GoogleTranslate!  Despite its many idiomatic dilemmas, running a search for "抹茶のタルト" provided me with precisely the information I needed.  After some initial translations back to English, I realized the recipes used metric measurements.  But with some math, baking intuition, and luck, I managed to make a dessert that brought me back to Japan.

The recipe involves making a matcha sponge cake crust, and then following that with the matcha mousse.  Plan for some refrigerator time, too--it'll need about 3 hours to set.

Thinking about being lost in translation, so to speak, and the memory of walking through the streets of Kyoto, it only makes sense to give you this song: here's Air's "Alone in Kyoto" from Sofia Coppola's Lost in Translation soundtrack.

Sponge Cake Ingredients:
--2 large eggs
--1/4 c. granulated sugar
--2 tbsp. unsalted butter, melted
--1/4 c. all-purpose flour
--2 tbsp. cornstarch
--1 tbsp. matcha

Mousse Ingredients:
--3 large egg yolks
--1/4 c. granulated sugar
--1/3 c. whole milk
--1 c. whipping cream
--2 heaping tbsp. matcha
--1 package gelatine
--2 tbsp. luke-warm water
--2 tbsp. hot water

Preheat oven to 325 degrees F.

Make the sponge cake crust first.  In a stand mixer, beat eggs and sugar until pale yellow.  Add butter and continue to mix on low speed.

In a medium-sized bowl, sift together cornstarch, flour, and matcha.  Slowly add, bit by bit, to the wet mixture in your stand mixer.  Mix on low speed until the dry ingredients are fully incorporated.

Line a springform pan with parchment paper and pour in your cake batter (there's not going to be very much of it at all, so don't be alarmed).  Bake for about 15 minutes or until a cake tester comes out clean.  Remove from oven and allow to cool.  Once it's done cooling, trim the edges so the cake fits in the bottom of a tart pan or a pie dish and refrigerate until you're ready for it.

Onto the mousse.  Clean your stand mixer bowl, and whisk the egg yolks and sugar until they're fully combined.  Set aside for just a minute or two.

In a small bowl, incorporate your gelatine into the 2 tbsp. of luke-warm water.  You'll need to whisk it just a bit.  Set aside (but not for too long--it'll begin to congeal).  In a pot, whisk together the matcha and the 2 tbsp. hot water.  It'll be just enough liquid to form a matcha paste.  Now add the whole milk over low heat and whisk constantly to incorporate.  Bring to a boil, and as soon as the milk begins to bubble around the sides, remove it from the heat.  Only after you've removed it from the heat and it has just started to cool, whisk in the gelatine.  (It's really important that the milk isn't boiling when you add the gelatine--it'll kill the gelatine.)

Add the green tea/milk mixture to the egg yolk mixture a bit at a time, and beat on medium speed for several minutes until it gets frothy.  Your green tea/milk mixture should be warm enough to temper the egg yolks.  

Now pour the whipping cream into a separate bowl and whisk until medium peaks form.  Slowly fold it into the green tea/milk mixture until it's incorporated.  You've got your mousse!

Remove your sponge cake crust from the refrigerator and pour the mousse mixture over it.  Cover very tightly with plastic wrap, being careful not to let the plastic wrap cling to the top of the mousse.  Refrigerate for at least 3 hours.

When you're ready to serve your matcha mousse tart, use a flour sifter to dust the top with matcha.  Serve chilled.