Step 1: Remove mascarpone from the fridge and let sit at room temperature for 30 minutes to soften.

Step 2: In a large mixing bowl, whisk egg yolks and sugar until pale yellow and thick, about 3 to 4 minutes.

Step 3: Add matcha powder, vanilla extract, and salt to the mascarpone and whisk gently until smooth and uniform, about 1 minute.

Step 4: Fold the matcha-mascarpone mixture into the egg yolk mixture using a spatula, preserving airiness.

Step 5: In a medium mixing bowl, whip cold heavy cream with an electric mixer until soft peaks form, about 2 to 3 minutes.

Step 6: Fold whipped cream into the matcha custard in two additions until fully incorporated.

Step 7: Pour cooled espresso into a shallow dish and stir in Kahlua if using; let sit for 1 minute.

Step 8: Quickly dip each ladyfinger into the espresso mixture for 1 second per side and arrange in a single layer in the baking dish.

Step 9: Spread half of the matcha custard over the ladyfingers, then repeat layering with remaining dipped ladyfingers and custard.

Step 10: Cover the dish with plastic wrap and refrigerate for at least 4 hours or up to 24 hours.

Step 11: Just before serving, dust the top generously with matcha powder using a fine-mesh sieve.