01 - Preheat oven to 300°F. Arrange four 6 oz ramekins in a deep baking dish.
02 - Blend persimmon pieces, 2 tablespoons sugar, and lemon juice in a blender or food processor until completely smooth.
03 - Distribute the persimmon puree evenly among ramekins, spreading into a thin layer at the bottom.
04 - Combine heavy cream and whole milk in a saucepan. Heat over medium heat until steaming but not boiling. Remove from heat.
05 - Whisk egg yolks, 1/4 cup sugar, vanilla extract, and sea salt in a mixing bowl until pale and slightly thickened.
06 - Slowly pour hot cream mixture into egg yolks while whisking continuously to prevent curdling.
07 - Pour custard through a fine mesh sieve into a measuring cup or pitcher to remove any lumps.
08 - Gently pour strained custard over the persimmon puree in each ramekin.
09 - Pour hot water into the baking dish until it reaches halfway up the sides of the ramekins.
10 - Bake for 35 to 40 minutes until custards are just set but still slightly wobbly in the center.
11 - Remove ramekins from water bath. Let cool to room temperature, then refrigerate for at least 2 hours or overnight.
12 - Sprinkle 1 teaspoon granulated sugar evenly over each chilled custard. Use a kitchen torch to caramelize until golden and crisp, or broil for 1 to 2 minutes.
13 - Let the brûlée rest for 3 to 5 minutes before serving to allow the caramelized crust to harden.