Step 1: Prepare the Crust
In a medium bowl, combine the flour and salt.
Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
Gradually add the cold water, stirring just until the dough begins to come together.
Form the dough into a ball, wrap in plastic wrap, and refrigerate for 30 minutes.

Step 2: Make the Filling
In a large bowl, whisk together the molasses, hot water, baking soda, vanilla, cinnamon, ginger, and beaten egg.
Stir until the mixture is well combined and smooth.

Step 3: Make the Crumb Topping
In a separate bowl, mix the flour, brown sugar, cinnamon, and salt.
Cut in the cold butter until the mixture forms coarse crumbs, using a pastry cutter or your fingers.

Step 4: Assemble the Pie
Preheat your oven to 375°F (190°C).
On a lightly floured surface, roll out the chilled pie dough to fit a 9-inch pie pan.
Transfer the dough to the pie pan, trimming any excess and crimping the edges.
Pour the molasses filling into the prepared crust.
Sprinkle the crumb topping evenly over the filling.

Step 5: Bake the Pie
Bake the pie for 30-40 minutes, or until the crust is golden brown and the filling is set. The topping should be lightly browned.

Step 6: Cool and Serve
Allow the pie to cool completely before slicing and serving.