Place the pie crust into a 9-inch pie plate. Pinch the edges around the edge of the plate.
In a medium bowl, whisk together the flour, sugar and cinnamon. Cut in the butter with a pastry cutter (or two knives) until the mixture resembles coarse crumbs.
In a separate bowl, whisk together the molasses, boiling water and baking soda.
Pour 1/3 of the molasses mixture into the unbaked pie crust. and sprinkle with 1/3 of the flour mixture. Continue alternating layers, ending with the flour mixture.
Bake for 35 to 40 minutes- or until the filling is set and the crumbs are golden.