Mix the flour, sugar, and shortening. Reserve 1/2 cup of the crumbs.
Pour hot water over the baking soda, add the molasses, beaten egg, vanilla and crumbs (not the reserved 1/2 cup). Pour into an unbaked pie shell and sprinkle with the remaining 1/2 cup of crumbs.
Bake at 425 degree farenheit oven for 10 minutes. Reduce the temperature to 350 degrees and bake until brown, apx 20-30 minutes.