Preheat your oven to 350°F (175°C). Butter the sides of a 10-inch springform pan.

Combine melted butter with chocolate cookie crumbs and press into the bottom of the pan. Bake for 10 minutes, then let cool.

Beat together cream cheese and softened butter until smooth. Gradually add sugar, sour cream, vanilla, and cornstarch. Incorporate the egg yolks one at a time.

Pour the filling over the cooled crust and bake in a water bath at 325°F (163°C) for about 1.5 hours until set.

Let the cheesecake cool in the oven for 30 minutes, then refrigerate for at least 4 hours, preferably overnight.

Make the salted caramel sauce by dissolving sugar and water, then simmering until golden. Whisk in butter and cream, then add sea salt.

Drizzle the cooled cheesecake with salted caramel and garnish with sea salt before serving.