In a medium mixing bowl, combine the finely crushed graham cracker crumbs, melted butter, brown sugar, and sea salt. Stir until the mixture resembles wet sand. Press firmly into a 9-inch springform pan. Freeze to set.
Place chopped white chocolate into a heat-proof glass bowl over simmering water. Stir constantly until 90% melted, remove from heat, and cool to room temperature. This prevents the chocolate from seizing.
Beat the room-temperature cream cheese until completely smooth. Add sour cream and vanilla paste, beating just until combined.
Slowly pour the cooled, melted chocolate into the cream cheese mixture while gently folding with a spatula until uniform in color.
In a chilled bowl, whip the cold heavy whipping cream and sifted powdered sugar until stiff peaks form. Do not over-whip.
Fold one-third of the whipped cream into the cream cheese mixture aggressively to lighten it. Then gently fold in the remaining cream to preserve volume.
Pour over the chilled crust, smooth the top, cover tightly, and refrigerate for at least 6 hours (preferably overnight) to set the structure.
