01 - Preheat oven to 300°F. Arrange four 6-ounce ramekins in a deep baking dish.
02 - Combine persimmon pieces, 2 tablespoons sugar, and lemon juice in a blender. Process until completely smooth.
03 - Distribute the persimmon puree evenly among the ramekins, creating a thin layer at the bottom of each.
04 - Warm the heavy cream and whole milk in a saucepan over medium heat until steaming. Do not allow to boil. Remove from heat.
05 - Whisk together egg yolks, 1/4 cup sugar, vanilla extract, and sea salt until the mixture appears pale and slightly thickened.
06 - Gradually pour the hot cream mixture into the egg yolks while whisking continuously to prevent curdling.
07 - Pass the custard through a fine-mesh sieve into a pouring vessel to remove any cooked bits and ensure smoothness.
08 - Gently pour the strained custard over the persimmon layer 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 the custards are set but still slightly wobbly in the center.
11 - Remove ramekins from the water bath. Let cool to room temperature, then refrigerate for at least 2 hours or overnight.
12 - Sprinkle 1 teaspoon of sugar evenly over each chilled custard. Use a kitchen torch to melt and caramelize the sugar until it forms a golden, crispy crust. Alternatively, broil under high heat for 1 to 2 minutes.
13 - Allow the caramelized topping to set for 3 to 5 minutes before serving.