Pulse graham crackers in a food processor until they reach a fine, sandy texture. Stir crumbs, granulated sugar, and melted butter until the mixture is evenly moistened.
Press the mixture firmly into the bottom of the pan using the flat base of a measuring cup to ensure a sturdy base.
Bake for 7–8 minutes until fragrant. Remove and let the crust cool completely before adding the filling.
Lower oven temperature to 140°C (280°F). Beat the room-temperature cream cheese, sugar, and vanilla bean paste until completely smooth.
Mix in the sour cream, eggs, and egg yolks on low speed. Tip: Avoid over-mixing here to prevent air bubbles that cause cracking.
Sift in the cornstarch and mix just until no white streaks remain.
De-Air: Pour the batter over the cooled crust. Tap the pan firmly on the counter 5–10 times to force air bubbles to the surface.
Bake for 60 minutes. The edges should be set, but the center should still have a slight "jello-like" jiggle.
Turn the oven off and prop the door open slightly. Let the cheesecake sit inside for 1–2 hours. This gradual temperature drop is the secret to a crack-free top.
Wrap tightly in plastic and refrigerate for at least 5 hours (preferably overnight) to fully set the custard texture.
Just before serving, sprinkle an even, thin layer of granulated sugar over the top.
Use a kitchen torch in constant circular motions until the sugar bubbles and turns deep amber. Let it harden for 2 minutes into a glass-like shell before slicing.
Notes
The Double-Torch: Sprinkle a thin sugar layer, torch until golden, wait 30 seconds, and repeat. This builds a thicker, glass-like "shatter" without overheating the cheesecake.
Low-Speed Mixing: Switch to the lowest setting once eggs are added. High speeds incorporate air, causing the cake to rise and collapse into a sunken, watery center.
The Humidity Fix: Sugar liquefies in moisture. If transporting, place a silica packet in the carrier, but for best results, torch on-site immediately before serving.
Suspended Vanilla Speckles: Ensure your batter is fully emulsified and thick before pouring. This prevents vanilla bean paste from sinking to the bottom of the crust.
The Perimeter Release: Run an offset spatula around the edges 10 minutes after baking. This allows the cake to shrink inward as it cools, preventing surface cracks.
Clean Rim Torching: Wipe stray sugar off the pan rim before torching. Burnt sugar on metal creates a bitter, carbonized aroma that taints the flavor of the cake edges.