Wow, I do love these cookies. They are unique but still approachable, and use black lime as the coloring to make them look like coal. Black lime is essentially brined and dried lime crushed into powder, so think of it as a slightly salty essence of lime. It turns out to be the perfect topping for a sweet and citrusy yuzu cookie.
Using a stand mixer or hand mixer, beat together the softened butter and sugar until light and fluffy, 2-3 minutes.
Add the yuzu juice, salt, baking soda and ginger and mix again.
Add the flour and mix on the lowest setting until a stiff dough forms.
Use a 1 tablespoon scoop to portion the dough into 15 dough balls that look like mounds. They won't change much in the oven, so make sure they are the size and shape you want to look like "coal."
Chill in the fridge for 8 hours up to to overnight.
The next day, preheat the oven to 350°F.
Bake the cookies for 14-15 minutes or until golden on the bottom. Let them cool completely.
While they are cooling, whisk together the powdered sugar and yuzu juice to make a glaze. Dip the tops of each cookie into the glaze, then flip them onto a cooling rack.
Dust the cookies with the black lime powder to make them look like coal. Give the glaze a few minutes to set and then they are ready to serve!