Preheat your oven to 450°F.

Separate the egg yolk from the whites and set the yolk aside.

Split the vanilla beans and scrape out the seeds.

In a large bowl, combine the cream cheese and mascarpone, then whip them on high until they are light and fluffy.

Gradually add the sugar in quarters, whipping well after each addition until it is fully incorporated.

Stir in the fine sea salt.

Add the whole eggs one at a time, beating well after each addition until they are fully mixed in.

Mix in the reserved egg yolk.

Add the vanilla bean seeds (or vanilla paste) and blend everything together.

Slowly pour in the heavy cream while continuing to beat the mixture.

Add the cornstarch gradually, mixing until it is fully hydrated.

Line a 9-inch springform pan with parchment paper, trimming any excess and creating a border as needed.

If desired, strain the batter through a fine-mesh sieve to achieve a smooth texture.

Tap the pan gently to release any air bubbles and smooth the surface.

Bake in the preheated oven at 450°F for 12 minutes, then rotate the pan and bake for another 12 minutes.

Lower the oven temperature to 325°F and bake for an additional 20 to 25 minutes, or until the internal temperature reaches 140°F.

Remove the cheesecake from the oven; the center should still be jiggly.

Allow it to cool to room temperature, then refrigerate for at least 4 hours or overnight.

Before serving, let the cheesecake sit at room temperature for a short while, then slice and enjoy.