Prepare the Crust: In a mixing bowl, combine all-purpose flour, kosher salt, and sugar. Cut in cold, unsalted butter until the mixture resembles pea-sized crumbs, then mix in cider vinegar and ice water until a dough forms. Chill for 1 hour.

Roll & Shape Crust: Roll out one disc of dough onto a floured surface until about 1/8 inch thick. Gently line a pie plate, allowing excess dough to hang over the edges, then chill again while you prepare the filling.

Make the Filling: In another bowl, combine diced fresh plums and figs with granulated sugar, dark brown sugar, potato starch, lemon juice, and spices. Gently toss until fruit is well-coated.

Assemble the Pie: Pour the filling into the prepared crust, making sure it’s evenly distributed. Roll out the top crust, cut into strips if making a lattice design, and place over the filling. Crimp the edges to seal.

Bake: Preheat the oven to 425°F. Brush the crust with an egg wash and sprinkle with demerara sugar. Bake for 20-25 minutes, then reduce the oven temperature to 375°F and bake for an additional 30-35 minutes until bubbling and golden brown.

Cool and Serve: Let the pie cool for 2-3 hours, allowing the filling to set. Serve at room temperature or slightly warm, enjoying every divine bite.