In a shallow bowl, whisk the matcha powder and hot water together until smooth and frothy. Set aside to cool slightly.
In a large mixing bowl, combine the chilled mascarpone cheese, cold heavy whipping cream, powdered sugar, and vanilla extract. Use an electric mixer to beat until stiff peaks form. Do not overmix.
Wash, hull, and finely dice the strawberries.
Working one at a time, quickly dip the ladyfingers into the matcha tea for just one second per side. Break them in half and press them into the bottom of 4 serving cups.
Add a layer of diced strawberries over the ladyfingers.
Spoon or pipe a layer of the mascarpone cream mixture over the strawberries.
Repeat the layers (ladyfingers, strawberries, cream) until the cups are filled.
Dust the tops with a fine layer of dry matcha powder and garnish with a fresh strawberry slice.
Chill in the refrigerator for at least 1-2 hours before serving to allow the ladyfingers to soften.