How to Make It
Roll pie dough to a 1/8-inch thick circle and place inside a greased 9-inch pie pan. Cut excess dough, leaving a 1/2-inch overhang. Fold overhang under itself, creating a thicker ring of crust around the pie’s edge. Crimp edge. Take a sheet of aluminum foil and grease it liberally with butter. Place buttered surface inside the pie shell, allowing the pie dough to come in direct contact with the aluminum foil. Freeze crust for 1 hour or overnight. Preheat oven to 350°F. Bake crust with aluminum foil for 25 minutes. Remove aluminum foil and use a spoon to press down any areas that have puffed up. Bake uncovered for an additional 5 minutes. Use a spoon to press down any puffed areas again and set aside to cool.
Increase oven to 450°F. In a mixing bowl, stir together flour, brown sugar, cinnamon, and salt until all ingredients are evenly distributed. Add butter and using your hands or a pastry cutter, incorporate butter into dry ingredients until no pieces of butter remain and mixture resembles cornmeal. Set aside.
In a separate bowl, whisk together molasses, boiling water, and baking soda until molasses is fully dissolved. Add beaten egg and whisk to incorporate. Pour liquid into pie shell. Sprinkle the reserved flour mixture evenly across the entire surface of the pie. Bake for 20 minutes, lower the oven temperature to 350°F and continue baking until the top begins to brown and the center of the pie is set, about 12 minutes. Allow pie to cool completely before slicing and serving with whipped cream, if desired.