Preheat oven to 325°F (165°C). Mix graham cracker crumbs, sugar, and salt; add melted butter and press into a 9-inch springform pan. Bake for 8-10 minutes until golden and cool.

In a mixer, beat cream cheese until smooth. Gradually mix in sugar, then sour cream, vanilla, salt, and cornstarch. Add eggs one at a time until just incorporated. Pour over the cooled crust.

Wrap pan in foil; place in a baking dish filled with hot water. Bake for 50-60 minutes until edges are set. Cool in the oven with the door ajar for 1 hour, then refrigerate for at least 4 hours.

Warm milk in a saucepan. Whisk egg yolks, sugar, cornstarch, and salt. Gradually whisk in milk, then return to the saucepan and cook until thickened. Chill covered with plastic wrap.

Spread chilled pastry cream over the cooled cheesecake. Refrigerate while preparing ganache.

Heat cream until steaming, pour over chocolate chips, and stir until smooth. Cool slightly and pour over pastry cream layer.

Chill cheesecake for 30-45 minutes before slicing with a warm knife. Serve chilled.