Green Tea Swiss Meringue Buttercream

When people ask me what my go-to baking recipe is, I tell them it's my red bean mochi cupcakes. They have a unique chewy texture because of the rice flour, and the red bean/green tea flavors complement each other well. Each time I make them, I'm finding out something new that improves the cupcakes.
I have another potluck tomorrow, so I decided to make these - not only are they different and novel to most people, they are also gluten-free, so everyone in my lab group can enjoy these! To switch it up this time however, I decided to make a Swiss meringue buttercream for the green tea frosting on top. Last time I made this buttercream, it turned out well, but took forever to make with my little six dollar hand mixer. Now that I have a Kitchenaid stand mixer, it was a lot easier and more efficient to make!

The other thing I did differently this time around was to flip these cupcakes upside-down for the frosting. For some reason, my cupcakes came out wider on the top. I've made these before without cupcake liners, but never had it fan out like this before. I believe it's because I may have filled the cupcake tins too full, causing them to spill out and widen out at top. The cupcake still turned out fine, so I simply flipped them over, for both aesthetic and stability reasons.

Toothpicks to protect frosting from tin foil lid I'm covering these with!

The end result was a cupcake that didn't quite look like a cupcake, but instead like a cute volcano with a green rose on top. Happy accident!

The recipe for these cupcakes is here, in a past blog post, but the recipe for the Swiss meringue buttercream is below.

Green tea Swiss meringue buttercream (enough to cover 2 dozen cupcakes)

• 3 egg whites
• 3/4 cup of white sugar
• Pinch of coarse salt
• 3/4 cup of butter (1.5 sticks) at room temp
• ~1/4 cup of green tea matcha powder
• 3 drop of green food coloring (optional)

1. Boil water in a small saucepan and place your stand mixer bowl on top of it so it forms a double boiler. (Try to not let the bottom of the bowl touch the bottom of the saucepan) In the bowl, whisk the egg whites with the sugar. Mixture will become frothy and slowly turn opaque white. The egg whites are ready when you pinch some between your fingers and it feels smooth. 
2. Transfer bowl to stand mixer (careful, bowl will be hot!) and use whisk attachment to continue beating the egg whites on medium-high speed. The egg whites will become shiny and stiff. 
3. When the bowl has cooled (about 10 minutes), slowly start adding the butter. I would cut the butter in cubes and add a cube every 15 seconds or so. The mixture will start curdling, but that's okay - keep beating and it will eventually go back to being pretty. 
4. Once all the butter  is added, add the green tea powder and food coloring. 
5. Keep beating until the buttercream is smooth. 
6. Use in any recipe you want! If not using right away, store in fridge for up to one week in an airtight container.