Preheat the oven to 325°F. Line the bottom of a 9-inch springform pan with parchment paper and lightly grease the sides.
Combine the graham cracker crumbs, melted butter, sugar, and salt until the mixture resembles wet sand.
Press the crust mixture firmly and evenly into the bottom of the springform pan. Bake for about 10 minutes, then remove and let it cool slightly.
Sift the matcha powder into a small bowl. Add the warm water and whisk until smooth and lump-free. Set aside.
Beat the softened cream cheese and sugar until smooth and creamy. Scrape down the sides of the bowl as needed.
Add the matcha mixture, heavy cream, sour cream, vanilla extract, and lemon juice. Mix gently until the filling is evenly combined.
Add the eggs one at a time, mixing on low speed just until each egg is incorporated. Avoid overmixing the batter.
Pour the matcha cheesecake filling over the cooled crust. Gently tap the pan against the counter to release large air bubbles.
Bake for about 50–55 minutes, or until the edges are set and the center still has a slight wobble.
Turn off the oven and leave the cheesecake inside with the oven door slightly open for about 30 minutes. This gradual cooling helps reduce cracking.
Remove the cheesecake from the oven and let it cool completely at room temperature.
Cover and refrigerate for at least 6 hours, preferably overnight, until completely chilled and firm.
Run a warm knife around the edge before releasing the springform pan. Slice with a clean knife, wiping the blade between cuts.
Dust lightly with matcha powder and garnish with fresh berries or whipped cream if desired. Serve chilled.