Preheat oven at 200°C/390°FPut inside, from the start, a big pan/casserole oven safe filled with water. Butter or line a 24 cm/9 inches diameter cake springform pan.
Melt the white chocolate and set aside, let it cool.
In a stand mixer or with a spatula mix well cream cheese, sour cream and sugar.
Add eggs one at time mixing well, the pour chocolate in a tiny stream mixing, see notes in the blogpost if you notice lumps.
Add now vanilla, lemon juice and salt.
Pour the batter into the springform and bake the cake at 200°C/390°F for the first ten minute then lower the temperature to 180°C/360°F and keep on baking for 45/55 minutes.
Take it off the oven when it's still quivering, let it cool completely then cover with cling film and let sit in the fridge for at least 6 hours, even better overnight.
Right before serving sprinckle light brown sugar on top and caramelize it with a burner or under the oven grill for few minutes ( pay attention not to burn it!)