Preheat the oven to 350°F (175°C) and prepare a greased springform pan.

Crush the digestive biscuits into fine crumbs and mix with melted unsalted butter. Press into the bottom of the springform pan and bake for 10 minutes before cooling.

In a bowl, beat softened cream cheese and granulated sugar until smooth. Incorporate eggs one at a time, then add vanilla extract.

Pour the cheesecake filling over the cooled crust and bake for 45 minutes. Turn off the oven and let it cool inside for an hour.

Allow the cheesecake to reach room temperature, then refrigerate for at least 4 hours or overnight.

For the caramel, combine sweetened condensed milk, brown sugar, and unsalted butter in a saucepan. Stir continuously for about 10 minutes until thickened.

Pour the caramel over the chilled cheesecake and return to the refrigerator for an hour.

Run a knife around the edges of the pan before releasing the sides. Slice and serve with whipped cream or sea salt.