In the bowl of a standing mixer, cream together butter, molasses, and both kinds of sugar. Beat for 5-10 minutes, scraping down the sides of the bowl occasionally, until light and fluffy.
In a separate bowl, whisk together the remaining dry ingredients. With the mixer on low, add the flour mixture a half cup at a time until completely combined.
Dump the dough out onto a floured surface and shape it into two disks. Wrap each in plastic wrap and chill in the fridge for at least 15 minutes up to overnight.
Bake the Cookies:
When ready to bake the cookies, preheat the oven to 350 degrees F and line two baking sheets with parchment paper.
On a clean, floured surface, roll out the gingerbread dough to about 1/8th inch thick. Cut the dough into fox (or any other shapes you prefer) with cookie cutters and transfer to the parchment lined baking sheets, leaving at least an inch between cookies.
Bake for 8-10 minutes, until the center of the cookies puffs up. Allow to cool on the trays for 5 minutes, and then transfer to cooling racks. The cookies should be room temperature (or cooler) before applying any icing (chill in the fridge if necessary).
Applying the Royal Icing:
To make the icing, beat together the egg whites, salt, and vanilla until frothy (about 8 minutes). Turn the mixer to low, and slowly add the powedered sugar until combined. Increase the speed to medium-high and whip the mixture until glossy, stiff peaks form (about 7 minutes). Transfer the icing to a piping bag with a small decorating tip.
Pipe the icing onto the cooled cookies. If you wish to add sprinkles, do so quickly - the royal icing will harden quickly!
Notes
Alternate Icing Options: As you see above. this recipe uses raw egg whites in the icing. If you are pregnant, have a compromised immune system, or are otherwise wary of using this ingredient, feel free to make substitutions.Another way to ice these gingerbread cookie foxes is with a thin powdered sugar glaze and a smattering of various sprinkles. While less defined as the royal icing, this method is a little quicker (and simpler) if you prefer, and does not use raw egg whites. Mix together two cups powdered sugar with two tablespoons milk. Add more liquid or more sugar until you have a viscous consistency that can coat the back of a spoon easily. Dip the front of your gingerbread cookies into the glaze and top with sprinkles of your choosing.