Step 1

Sprinkle some flour onto a clean flat surface. Roll the dough into a flat round wide enough to fit a 9-inch deep-dish pie plate. Fit the dough into the bottom and sides of the pie plate and trim the edges. Refrigerate it for 30 minutes.

Step 2

Prepare the filling. Mix the brown sugar, molasses, egg, flour, and baking soda in a large bowl. Gradually pour in boiling water and stir. Allow the filling to cool completely.

Step 3

Preheat the oven to 425 degrees Fahrenheit.

Step 4

Line the crust with aluminum foil and fill it with pie weights, uncooked rice, or dried beans. Place the crust on the lower rack of the oven and bake it for 15 minutes. Remove the weights and foil. Brush the crust with a slightly beaten egg yolk. Bake it for another 5 minutes. Allow the crust to cool completely on a wire rack.

Step 5

Lower the oven heat to 350 degrees Fahrenheit and make the topping. Whisk together the flour, brown sugar, baking soda, and salt until well combined. Using a pastry cutter or fork, cut in the butter cubes until the mixture is crumbly.

Step 6

Pour the pie filling into the crust and sprinkle with the crumble topping. Cover the pie with aluminum foil and bake it for 45 to 50 minutes, or until the filling has set and is golden brown. Cool it completely on a wire rack, for about 2 hours. Slice, serve, and enjoy!