Preheat oven to 350°F (175°C). Combine graham cracker crumbs, sugar, and melted butter; press into the bottom of a 9-inch springform pan. Bake for 8-10 minutes.

Beat cream cheese and sugar until smooth. Beat in sour cream and vanilla. Add salt, then eggs one at a time, mixing well after each addition.

Pour filling over the cooled crust.

Place springform pan in a larger roasting pan; pour boiling water halfway up the sides. Bake for 50-60 minutes, or until set around edges but the center still jiggles slightly.

Turn off oven; leave cheesecake in with the door ajar for 1 hour. Cool completely, then refrigerate for at least 4 hours.

For the caramel: Combine sugar and water in a saucepan over medium heat. Cook, swirling occasionally, until deep amber. Carefully pour in heavy cream (it will bubble). Whisk until smooth.

Remove from heat; stir in butter and salt until melted. Let cool slightly before pouring over the chilled cheesecake. Refrigerate for at least 30 minutes before serving.