Prepare the oven and pan. Preheat oven to 425°F. Line 3-inch deep 6-inch round cake pan with 2 layers of parchment paper, allowing the paper to extend about 2-inches above cake pan rim. Set aside.
Make the Crust: Blend the vanilla wafers. Using a food processor or blender. Mix the crushed vanilla wafers, melted butter, and salt. Transfer to the prepared cake pan. Press into an even layer into the bottom of the pan.
Prepare the vanilla cheesecake filling. Place cream cheese and sugar in a stand mixer fitted with the blade attachment. Beat on medium until the mixture is smooth. Add in vanilla. With the mixer running, add eggs one at a time. Scrape down the sides of the bowl. Separate into 2 bowls of equal portions.
Mix flour and heavy cream. In a small bowl, stir together flour, salt, and about 1/4 cup of cream until paste forms. Slowly add remaining cream, a little at a time, until the mixture is smooth and has no lumps. Separate into 2 bowls of equal portion.
Pour one of the flour and heavy cream bowls into the vanilla cream cheese filling bowls. Whisk thoroughly until incorporated
Make the Matcha cream cheese filling. In a small separate bowl, mix the 12 g matcha and 3 tbsp of heavy cream. Mix this into one of the flour and heavy cream bowls. Pour the matcha and heavy cream mixture into the second of the cream cheese mix bowls. Whisk thoroughly until incorporated.
Assemble the layers. Pour matcha mixture into prepared cake pan on top of crust. Put the vanilla cheesecake batter into a piping bag and carefully pipe on top of the matcha batter.
Bake. Place filled cake pan on a baking sheet to catch any spills during baking. Place in the center of the preheated oven. Bake for 35-40 minutes until the top is browned yet the center is still jiggly. Let cheesecake cool in the pan to room temperature, then unmold from the pan.
Serve at room temperature for the soft custard-like texture or chill overnight if you want a more firm texture.