Cream the Butter: Add the softened butter to a large bowl and beat with a hand mixer on low speed until light and smooth, 2 to 3 minutes. You can also use a stand mixer.
Form the Dough: Add the powdered sugar, vanilla, and salt to the bowl. Beat again until smooth, about 1 minute. Add the flour, turmeric, cinnamon, ginger, cardamom, and black pepper. Beat one final time on low speed, until there is no more dry flour and the spices are evenly incorporated. The dough should look crumbly, but will stick together when pinched.
Knead & Chill: Use your hands to press the dough together, then knead it a few times to form a ball. Flatten the ball into a disc, cover in plastic wrap, and chill in the fridge for at least an hour, or up to overnight.
Oven Prep: Preheat the oven to 350F. Line a large baking sheet with a silicone mat or parchment paper and set aside.
Form the Cookies: Generously dust a cutting board and rolling pin with flour. Unwrap the dough and place on the cutting board; if the dough does not look completely smooth, knead it a few times to help the gluten develop some. Roll the dough out until it is around 1/4” thick, then use a cookie cutter to form cookies. Transfer each cookie to the baking sheet (a bench knife makes this easy!), leaving about 1/2” of space between each cookie.
Repeat: Knead the remaining dough back together and repeat step 5 until there is no remaining cookie dough. Dust your cutting board with more flour if things start to stick.
Bake: Bake in the middle rack of the oven for 5 minutes, then rotate the baking tray (to help the cookies cook more evenly) and bake for an additional 5 minutes.
Cool: Remove from the oven and let sit on the baking tray for 10 minutes to set. Use a spatula to transfer the cookies to a wire rack and let them cool completely.
Make the Icing: Add the powdered sugar to a small bowl along with the cardamom and 1 tablespoon (3 teaspoons) of milk. Whisk well to form a smooth frosting. The frosting should be easy to drizzle, so add additional liquid in 1 teaspoon increments until it reaches your desired consistency.
Decorate: Drizzle or spoon the icing over the cookies; I would not recommend dunking them, as they are delicate and may break. Sprinkle the toasted coconut over the wet icing and return to the wire rack.
Serve & Store: Let the cookies rest until the icing sets and is firm, which can take up to 1 hour. Once firm, store the cookies in an airtight container at room temperature for up to 5 days.