Fill a pot with about an inch of water and bring it to a boil. In a large mixing bowl that fits snugly over the pot without touching the water, whisk together the egg yolks and granulated sugar. Once the water is boiling, turn off the heat and place the bowl on top of the pot to create a double boiler. Whisk the egg mixture continuously until the sugar dissolves and the mixture turns pale, about 5 minutes. Remove the bowl from the heat and immediately add the softened mascarpone cheese, whisking until smooth and silky. Set aside. In a separate bowl, combine the whipping cream, sifted matcha powder, and vanilla extract. Using an electric hand mixer with a whisk attachment, whip the cream to medium peaks—structured enough to hold shape but still fluid and not fully stiff. Gently fold the whipped cream into the mascarpone mixture with a spatula until no streaks remain. Set aside.

In a shallow bowl, mix together the matcha powder, granulated sugar, and hot water. Whisk with a matcha whisk, milk frother, or regular whisk until the mixture becomes slightly frothy, about 30 seconds. Quickly dip each ladyfinger into the matcha soak, coating both sides just enough without letting it sit or soak through to avoid becoming mushy. Let any excess liquid drip off, then arrange the ladyfingers in an even layer at the bottom of your serving dish. Repeat to create a flat, uniform base.

Spread a generous layer of the mascarpone cream evenly over the ladyfingers using a spatula. Add another layer of matcha-soaked ladyfingers followed by a second layer of mascarpone cream. Cover and refrigerate the tiramisu for at least 4 hours or, preferably, overnight to allow the cream to firm up and the ladyfingers to soften properly.

Just before serving, dust the top of the tiramisu generously with matcha powder.