Preheat oven to 350F and spray two 6" cake pans with baking spray. In a small bowl, whisk together the ground flaxseed with the water and set aside to thicken.
In the bowl of a stand mixer, combine the flour, baking powder, baking soda, salt, sugars, cinnamon, ginger, nutmeg, and cloves.
Add in the vegan butter, and beat on low until it's incorporated and has a sandy texture.
In a small bowl, whisk together the oil, flaxseed mixture, nondairy yogurt, fresh grated ginger, molasses, and vanilla extract, and add them to the dry ingredients. Mix until combined.
Pour in the unsweetened nondairy milk, and beat on medium-low until smooth and creamy.
Finally, fold in the crystallized ginger.
Divide batter evenly among the two pans, and bake for 35-40 minutes, until a toothpick inserted in the center comes out clean.
Let cool slightly in the pans, then turn out onto cooling racks to finish cooling.
When the cakes are completely cooled, you can make the frosting. In the bowl of a stand mixer, beat the shortening, vegan butter, vanilla extract, ginger, and cinnamon together until completely smooth and creamy. Add in the powdered sugar, 1 cup at a time, until a thick frosting forms. Add in the salt. It is normal to need to add 1-2 tablespoon of milk to get the right consistency.
To assemble the cake, divide the 2 cake layers in half to create 4 thin layers.
Place one cake piece on your cake stand or platter, and spread some frosting on top. Repeat with all.
Next, cover the cake with the remaining frosting. I always like the "naked" look, so I cover the cake and use a bench scraper to get rid of any excess. Repeat to fill any gaps!
Grab your store-bought gingerbread man cookies, and pick the prettiest ones to create a border around the bottom of the cake. You may need to pipe a little dollop of frosting on the back of the cookies to get them to stay in place.
Crush 3-4 cookies and sprinkle the crumbs on top of the cake.
Finally, for the border, spoon the remaining frosting in a piping bag fitted with a 4B tip. Pipe in a coil/spiral motion to create the rope effect.
Let cake chill in the fridge for 30 or more minutes before serving. Enjoy!