Matcha Whoopie Pies

Based on Whoopie Pies

= For the Cakes

2 cups flour 1/2 cup Dutch-process cocoa powder 1 1/2 teaspoons baking soda 3/4 teaspoon fine sea salt 1/2 cup unsalted butter, at room temperature 1 cup packed dark brown sugar 1 large egg 1 teaspoon vanilla extract 1 vanilla bean, split lengthwise and seeds scraped out 1 cup buttermilk

For the Matcha Filling

1 1/2 cups powdered sugar 1 1/2 tablespoons matcha 3 oz cream cheese 3 oz mascarpone 6 tablespoons unsalted butter, at room temperature

Instructions

1. Preheat oven to 350°. Sift flour, cocoa, baking soda, and salt into a medium bowl.
2. Beat butter and brown sugar in a large bowl with a mixer on medium speed until very fluffy, 3 to 4 minutes.
3. Beat in egg, vanilla extract, and vanilla seeds. Reduce speed to low and gradually add flour mixture; then gradually beat in buttermilk until smooth, scraping down inside of bowl as needed.
4. Line 2 large baking sheets with parch­ment paper or Silpat mats*. Put batter in a piping bag with a large tip (or cut a 1/2-in. corner off a resealable plastic bag and spoon in batter). Form 1-tbsp. mounds of batter 2 in. apart on sheets. Bake about 12 minutes or until cakes spring back when poked. Transfer to rack to cool.
5. Meanwhile, make filling: Sift powdered sugar and matcha together into a medium-large bowl. Add cream cheese, butter, and mascarpone and beat with a mixer on low speed at first, then on medium until very smooth and creamy, about 2 to 3 minutes.
6. Using an offset spatula or a butter knife, generously spread some filling on the flat side of a cake and top with another cake. Repeat for rest of cakes.