Melt the 2 cups of chocolate over a bain marie or in the microwave (stirring every 30 seconds). Set aside to cool.
In the bowl of a stand mixer or using a food processor, use the back of a rubber spatula to smooth down the cream cheese. With the paddle attachment, mix the cream cheese until it’s smooth and there are no lumps. Add the sour cream and sweetened condensed milk and mix to combine. Add the melted chocolate, vanilla and fine sea salt and combine.
Once the chocolate is cool, keep the mixer on low and pour it into the bowl. Once it’s fully incorporated add the eggs one at a time, mixing to just combine each before adding another. Careful not to overmix the eggs. Stir in the salt.
Pour filling into the chilled crust (if you see bits in the filling pour into the crust through a mesh sieve to remove them).
If using a cake pan: Set the pan into a 13 x 9” cake pan and fill it halfway with hot water. Set the cheesecake and it’s water bath into the middle rack of the oven. If using a springform pan, place the water bath on the rack underneath the cheesecake.
Bake for about 1 hour, until the sides look set and the center is still slightly jiggly. Once it’s done, shut off the oven and use a wooden spoon to prop open the door. This lets the cheesecake cool slowly. After 30 minutes, remove the cheesecake from the oven (and the water bath) and let the cheesecake cool to room temperature on the counter. Then set in the fridge overnight.