In a bowl whisk together the egg yolks and sugar until thick and smooth. Whisk in the pumpkin pie spice.

Take 1 cup of the hot milk mixture and quickly whisk it into the egg yolk mixture, stirring constantly. Pour this mixture back into the hot milk in the double-boiler, stirring constantly. Cook over medium heat until the mixture thickens and coats the back of a wooden spoon, about 20 minutes. Strain into a bowl and whisk in the pumpkin. Let the custard cool to room temperature and then cover and refrigerate overnight.

Pour the custard mixture into an ice cream maker and process, about 15 minutes. Note: The ice cream will have a thicker texture than regular ice cream due to the pumpkin. Keeps frozen for up to two weeks.

Heat the oven to 350º. Grease and flour an 8 x 8 x 2 baking pan.

In a mixing bowl with the mixer running, cream together the shortening, butter and sugar until blended. With the mixer running, add the egg and molasses and beat thoroughly to combine. In another bowl, sift together the flour, salt, soda, ginger and cinnamon. Add the dry ingredients to the creamed mixture and beat at slow speed to combine. With the mixer running, add the hot coffee and beat thoroughly to combine. Spread the batter in the prepared pan and bake until done, about 30 minutes.

Let the gingerbread cool for about 30 minutes. Cut the gingerbread into individual serving squares and serve with a scoop of pumpkin pie ice cream. Garnish each plate with some of the crystallized ginger.