Preheat oven to 425°F. Make sure your pie crust is in a pie dish ready to go and set it aside.
1 9-inch refrigerated pie crust
In a large bowl, combine the all-purpose flour, 1 tablespoon brown sugar, ground ginger, and allspice. Add in the butter and mix together with a pastry blender until the butter has broken down and the mixture takes on the appearance of coarse meal. Set aside.
¾ cup all-purpose flour, 13 tablespoons brown sugar, ¼ teaspoon ground ginger, ¼ teaspoon ground allspice, 5 tablespoons unsalted butter
In a separate, medium bowl, mix the hot water, molasses, chocolate pudding mix, remaining ¾ cup brown sugar, vanilla extract, and baking soda together until everything is combined. Whisk in the egg and then pour into the pie crust.
1 cup water, ½ cup unsulphured molasses, 3 ounces instant chocolate pudding mix, 1 teaspoon pure vanilla extract, ¼ teaspoon baking soda, 1 large egg
Carefully sprinkle the crumble mixture on top of the molasses layer and then place in the oven.
Bake in the oven for 15 minutes.
Lower the temperature to 350°F and bake for another 30 minutes.
Remove from the oven and let cool before serving.