Authentic Pennsylvania Dutch Shoo Fly Pie

1/2 c Baking Molasses

1 Egg Yolk

1/2 t Baking Soda

3/4 c Boiling Water

3/4 c Flour

1/2 c Brown Sugar

2 T Butter

1/8 t Nutmeg

1/8 t Ground Ginger

1/8 t Ground Cloves

1/2 t Cinnamon

1/4 t Salt

1 Pastry for 9 inch pie

Dissolve soda in boiling water and add to egg and molasses. Set aside. Stir dry ingredients together, mixing well. Cut in shortening until mixture looks like coarse crumbs. Pour molasses into pie shell. Sprinkle crumbs evenly over top. Do not stir. Bake at 450 degrees for 15 minutes then reduce heat to 350 degrees and bake 20 minutes longer. Cool and serve.