Rich, molasses-filled shoofly pie with a crumb topping is a beloved Pennsylvania Dutch family tradition. This unique, deeply flavored pie is a distinctive American regional dessert.
Preheat oven to 400°F. Place the unbaked pie crust into a 9-inch pie pan and set aside.
Combine flour, brown sugar, ground cinnamon, and salt in a mixing bowl. Cut in cold butter with fingertips until mixture is crumbly and pea-sized.
In a separate bowl, whisk together molasses, warm water, beaten egg, and baking soda until frothy and bubbly.
Pour the molasses mixture into the prepared pie shell, then evenly sprinkle the crumb topping over the liquid center—do not stir.
Bake at 400°F for 10 minutes, then reduce heat to 350°F and bake for 35–40 minutes more, until the crumb top is golden and the center is set with a slight jiggle.
Cool the pie completely on a wire rack before slicing to ensure proper setting and prevent crumbling.