How to Make It
Prepare the Pecan Streusel: Whisk together flour, sugars, cinnamon, nutmeg, and salt in a bowl. Using your fingers, rub butter into dry ingredients until mixture is crumbly and forms large, moist clumps. Add pecans, and work into clumps until incorporated. Refrigerate until mixture is very cold and firm, 1 to 2 hours. (Or cover bowl, and refrigerate up to 2 days.)
Prepare the Crust: Preheat oven to 375°F. Unwrap chilled pie dough disk from Single-Crust Pie Pastry, and place on a lightly floured surface. Let stand at room temperature until slightly softened, about 5 minutes. Sprinkle dough with flour, and roll into a 12-inch circle. Carefully fit dough circle into a 9-inch deep-dish glass pie plate, leaving a 1/2-inch overhang. Fold edges under.
Prepare the Persimmon Filling: Place persimmon puree in a large saucepan over medium-high; bring to a boil. Reduce heat to medium-low, and simmer, stirring often, until reduced to 2 cups, about 30 minutes. Pour puree on a rimmed baking sheet to quickly cool, about 10 minutes, stirring occasionally.
Stir together sugar, flour, cinnamon, nutmeg, and kosher salt in a small bowl until well combined. Add melted butter to sugar mixture, stirring with a fork until mixture is evenly combined and resembles damp sand.
Stir together evaporated milk and eggs in a medium bowl. Add sugar-butter mixture, and stir until mixture is smooth and creamy. Add persimmon puree, and stir until well combined.
Pour filling into piecrust. Bake in preheated oven until filling is partially set (has lost its initial liquid texture and overall shiny surface), 25 to 30 minutes.
Remove pie from oven. Reduce oven temperature to 350°F. Using your fingers, break cold Pecan Streusel into small clumps, and sprinkle over center of pie. Return pie to oven, and bake until pie filling is firm, puffed up, and set, 25 to 30 minutes. Transfer pie to a wire rack, and cool to room temperature, about 3 hours.