Preheat the oven to 325°F (160°C).
Combine graham cracker crumbs, sugar, and melted butter until evenly mixed.
Press the mixture firmly into the bottom of a 9-inch springform pan and bake for 8 to 10 minutes. Remove and let cool.
Beat cream cheese and sugar until smooth and creamy, about 2 to 3 minutes.
Add vanilla extract and mix well.
Add eggs one at a time, mixing just until combined after each addition to avoid overbeating.
Stir in melted white chocolate and heavy cream until the filling is silky smooth.
If using, gently fold in the cornstarch for extra stability.
Pour the filling over the cooled crust and bake for 55 to 65 minutes, until the edges are set but the center still jiggles slightly.
Turn off the oven, crack the door open, and let the cheesecake cool inside for 1 hour.
Refrigerate the cheesecake for at least 4 hours or overnight for best texture.
Before serving, run a knife around the edges and use a hot, wiped knife for clean slices.
Optionally, garnish with white chocolate shavings, fresh berries, or whipped cream.