1. Preheat the oven to 350°F (175°C).

2. In a medium bowl, mix the flour, salt, and melted butter until the texture is crumbly.

3. Press the crumb mixture firmly into the base and sides of a 9-inch (23 cm) springform pan.

4. Bake the crust for 15 to 20 minutes, or until lightly golden.

5. Allow the crust to cool completely at room temperature.

6. In a small bowl, gently separate the caviar with a fork, being careful not to break the eggs too much. Cover and chill in the refrigerator until needed.

7. In a large bowl, beat the ricotta cheese until smooth and free of lumps.

8. Add the sugar, eggs, vanilla extract, and heavy cream to the ricotta cheese. Mix on medium speed until the filling is creamy and well blended.

9. Pour the filling over the cooled crust and use a spatula to smooth the surface evenly.

10. Bake at 350°F (175°C) for 45 to 50 minutes, until the edges are firm and the center still has a slight wobble.

11. Cool the cheesecake completely in the pan on a wire rack.

12. Chill in the refrigerator for at least 4 hours or overnight.

13. Just before serving, place a layer of chilled caviar over the top of the cheesecake.

14. In a small bowl, mix the crème fraîche and melted butter until combined. Add small spoonfuls of the crème fraîche sauce on top of the caviar.

15. Finish with a light sprinkle of finely chopped fresh herbs, lemon zest, and a pinch of salt to taste.

16. Carefully remove the cheesecake from the springform pan and serve chilled.