Ingredients
Method
Whisk 3 cups (375 g) all-purpose flour and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt in a medium bowl to combine. Using your hands or a pastry cutter, work in 1 cup vegetable shortening until largest pieces are pea-size.
Whisk together 1 large egg, beaten to blend, 1 Tbsp. distilled white vinegar, and ½ cup ice-cold water in a small bowl. Add to dry ingredients and mix with your hands until incorporated.
Divide dough into 2 portions (note: recipe makes enough dough for 2 pie crusts). Roll out 1 portion on a lightly floured surface to a 10" round. Transfer to a 9"-diameter pie pan. Lift edges and allow dough to slump down into pan, then press dough firmly into bottom and sides and crimp the edges as desired. Chill pie shell until firm, at least 1 hour and up to 2 weeks (cover tightly in plastic wrap if chilling longer than 1 hour). Form remaining dough into a disk, wrap in plastic, and chill up to 2 weeks (or freeze up to 1 month).
Preheat oven to 375°. Mix 1 cup (125 g) all-purpose flour, ⅔ cup (packed; 134 g) brown sugar, and 1 Tbsp. vegetable shortening in a heatproof medium bowl to combine. Set aside ½ cup flour mixture for topping.
Add 1 large egg, 1 cup (generous) unsulfured molasses, and 1 tsp. baking soda to remaining flour mixture in bowl and mix to combine. Pour in ¾ cup boiling water and mix, scraping down sides of bowl, until incorporated.
Pour molasses filling into crust; evenly scatter reserved flour mixture over filling. Bake pie 18 minutes. Lower oven temperature to 350° and continue to bake until crust is golden and filling is slightly wobbly in the center when pan is gently shaken, 18–20 minutes longer. Transfer pie to a wire rack and let cool at least 2 hours before serving.
Cut pie into wedges and serve with vanilla ice cream or whipped cream.