Step 1: Whisk 2 tablespoons of matcha powder into 1 cup of hot water until smooth and no lumps remain. Set aside to cool to room temperature.
Step 2: In a heat-proof bowl over a pot of simmering water, whisk egg yolks and sugar together until the mixture is pale and thick (about 5-7 minutes). Remove from heat and let cool.
Step 3: In a separate bowl, beat the heavy whipping cream and vanilla extract until stiff peaks form.
Step 4: Fold the room-temperature mascarpone into the cooled egg yolk mixture until smooth, then gently fold in the whipped cream.
Step 5: Quickly dip each ladyfinger into the cooled matcha tea and place them in a single layer in an 8x8 inch glass dish.
Step 6: Spread half of the mascarpone mixture over the ladyfingers. Repeat with another layer of dipped ladyfingers and the remaining cream.
Step 7: Cover and refrigerate for at least 4 hours, preferably overnight. Dust with extra matcha powder just before serving.