Start by crushing the Oreo cookies into fine crumbs using a rolling pin or food processor. Mix the crumbs with melted butter until evenly coated. Press the mixture firmly into the bottom of a lined springform pan to create an even crust. Set it aside while preparing the filling.
In a large bowl, beat the softened cream cheese, sugar, and vanilla extract until smooth and creamy. Add the eggs one at a time, mixing gently after each addition. Sift in the matcha powder and mix just until combined, making sure the color is even and vibrant.
Pour the matcha cheesecake batter over the prepared Oreo crust and smooth the top. Bake in a preheated oven until the edges are set and the center still slightly jiggles. Cover loosely if needed and continue baking until fully set. Let the cheesecake cool completely at room temperature.
Once cooled, refrigerate the cheesecake for several hours until firm. Whip the heavy cream with sugar until soft peaks form. Spread or pipe the whipped cream over the chilled cheesecake and finish with a light dusting of matcha powder if desired.