In a large saucepan, melt the shortening over medium-low heat. Remove the saucepan from the heat, add sugar and molasses, and stir to combine. Keep stirring until the sugar is completely dissolved. Set aside to cool slightly.
In a medium bowl, sift the flour, baking soda, ginger, nutmeg, and salt to whisk and combine.
Slowly add 2 cups of the flour mixture to the saucepan with the molasses mixture ½ cup at a time and stir to combine. Place the dough on your counter or a silicone baking mat and add the remaining flour mixture. Use your hands to mix the remaining flour mixture into the dough, making sure it's thoroughly combined.
Preheat the oven to 375°F. Divide the dough into three equal pieces and roll each into a ball with your hands. Place each ball of dough on a silicone baking mat or a piece of parchment the size of a baking sheet. Roll each ball of dough into a rectangle ¼ inch thick.
Using a gingerbread house cookie cutter, cut the shapes you will need for the house (most likely 2 front/back, 2 side, and 2 roof pieces). Leave space between the cookie cutters when cutting the shapes so that there's space between the pieces when baking. Remove the excess dough from around the cut out shapes without moving the cut pieces. If you wish to cut any additional shaped into your gingerbread house (such as windows or doors), carefully cut the shapes using a knife but do not remove the extra dough, as it will help to hold the cut shape when the gingerbread bakes.
With just the cut out shapes remaining on your silicone baking mats or parchment paper, transfer the mats or papers to baking sheets. Bake the baking sheets one at a time for 13 to 15 minutes or until the gingerbread pieces just begin to darken around the edges.
Remove the tray from the oven and place the tray on a wire cooling rack. If you've cut any additional shapes into the dough, carefully recut those immediately after removing the tray from the oven while the gingerbread is still soft. Allow the gingerbread to cool completely on the tray. Once cool, do one final recut of any additional shapes and carefully remove the spare pieces.