About 10 minutes before the cookies are ready to be removed from the fridge, cover a baking sheet with parchment paper and preheat the oven to 350F.
Next, remove the bowls of dough from the fridge. Scoop the cookie dough into 1 tablespoon balls (around 20 grams per dough ball). Then take 1 tablespoon of each flavor dough (matcha, sweet potato, and charcoal), press together, and gently roll into a ball between your palms. Then, roll each cookie dough ball in the bowl of the remaining ¼ cup sugar that was set aside until coated.
Place the cookie dough balls onto the parchment-lined baking sheet. Then, slightly press each dough ball down with your palm. Make sure that each cookie is kept about 2 inches apart since they will spread slightly while baking. Then, press a few eyeball sprinkles into each cookie (making sure to save some to add after baking).
Add the tray to the oven and bake the cookies for 11-13 minutes until the bottoms are lightly browned and the cookie edges are fully cooked with soft centers. The cookies will continue baking after they are removed from the oven so the centers should be soft and just cooked, but not glossy or raw, when they are removed from the oven.
Remove the cookie tray from the oven and immediately tap the tray on the counter to produce a more “wrinkly” cookie. Then, while the cookies are still warm, press in any remaining googly eyeball sprinkles so they stick. At this point, you can also swirl the warm cookies between a round pastry/cookie cutter to make them round.
Let the cookies cool on the baking sheet for 5 minutes. The cookies will be soft and puffy out of the oven and will naturally deflate a little while cooling. After 5 minutes, move to a wire cooling rack to finish cooling. Enjoy!