Ginger sugar cookies

I made these for my logic class before their last exam. The students, unfortunately, didn't do so well, but the cookies were great. Also unfortunately, I didn't think to get a picture before they were all eaten. (The cookies, not the students.)

But come on, you know what sugar cookies look like.

Adapted from The America's Test Kitchen family cookbook
Ingredients
2 cups sugar
2 1/2 cups AP flour
1/2 tsp baking powder
1/2 tsp kosher salt
14 tbsp (1 3/4 sticks) vegan margarine, room temperature
2 tsp vanilla extract
1 tbsp potato starch
about 1/4 cup water
1 tsp freshly-grated ginger root
2 tbsp diced candied or crystallised ginger

Instructions
1. Process the granted ginger with 1/2 cup of the sugar in a food processor for about 10 seconds. Spread the ginger sugar in a shallow dish.
2. Adjust an oven rack to the middle position. Preheat the oven to 350*F. Whisk flour, baking powder, and salt together in a bowl.
3. Using an electric mixer, cream the remaining 1 1/2 cups of sugar and margarine on medium speed until light and fluffy, 3-6 minutes. Add the vanilla, starch, and diced ginger, and mix thoroughly, another minute or so. Scrape down the bowl and beaters as needed.
4. Reduce the mixer speed to low and add the flour mixture in 3 batches, combining thoroughly before adding the next batch. Add the water as needed to keep the dough from drying out. The result should be sticky and slightly thin but not runny. Fold a few times with a spatula to make sure there are no pockets of flour remaining.
5. Using wet hands, form balls of dough 1 1/2-2 tbsp (I use a number 18 disher to get uniform cookies). Roll the balls in the ginger sugar to coat and arrange on parchment paper, about 12 to a sheet. Flatten each cookie and sprinkle with any remaining ginger sugar.
6. Bake the cookies one sheet at a time for 10-14 minutes, turning halfway through, until the edges are just starting to turn brown. Cool on a baking rack for about 10 minutes.