In a medium pot, stir together the molasses, sugar, corn syrup, and water and bring the mixture to a boil, stirring constantly with a wooden spoon or silicone spatula, over high heat. Once the mixture is boiling, reduce the heat to low and maintain a gentle boil, stirring frequently, for 5 minutes.
Remove the pot from the heat and stir in the vegetable shortening until the mixture is smooth. Set aside to cool to room temperature, about 30 minutes.
Sift the flour, speculoos spice mix, ginger, baking soda, and salt into a large bowl and stir together.
Once the molasses mixture has come to room temperature and is the same texture as molasses, mix it into the flour mixture until a dough has formed and no dry flour remains. Bring the dough together into a rough disc, then wrap it tightly in plastic wrap and refrigerate it for at least 4 hours or up to 24 hours before rolling it out.
Preheat the oven to 350°F (180°C). Line 4 baking sheets with parchment paper or silicone baking mats.
On a lightly floured work surface, roll out the dough very thin, about
1/16 -inch thickness. Move the dough around and check underneath it frequently to make sure it is not sticking to the work surface, dusting lightly with more flour as needed. Using a 2½-inch-wide star-shaped cookie cutter, cut out the cookies and place 24 on each of the prepared baking sheets, evenly spaced.
If there is any flour on your cookies, brush it off with a dry pastry brush before baking. Bake for 10 to 12 minutes, or until the cookies have puffed up and appear dry. Allow the cookies to cool completely on the baking sheets before removing.