Preheat the oven to 450°F for convection or 475°F for conventional ovens and position the rack in the middle or slightly higher.
Line a 6-inch round cake pan with two overlapping parchment sheets, leaving 2 inches of overhang on each side.
Soften cream cheese if needed by microwaving at 50% power for 45 seconds.
Beat the cream cheese and sugar together until smooth and fluffy.
Whisk eggs in a separate bowl and gradually add them to the cream cheese mixture, one-third at a time, until fully incorporated.
Add lemon juice and mix thoroughly.
Sift in the flour and cornstarch slowly while stirring to prevent lumps.
Stir in kosher salt.
Gradually pour in heavy cream while mixing until the batter is silky and smooth.
Pour the batter into the lined pan in one motion to avoid air bubbles.
Tap the pan on the counter to release bubbles and use a toothpick to pop any remaining.
Place the pan on a baking sheet and bake for 30–35 minutes until the top is deeply browned and the center is jiggly.
Let the cheesecake cool in the pan on a wire rack for 2–3 hours.
Chill for 4 hours for a firmer texture or serve at room temperature for a molten center.
Remove from the pan, peel back the parchment, and slice to serve.