Preheat oven to 360° F.
Using a hand mixer, stand mixer, or mixing bowl with wooden spoon, beat the coconut oil until soft and fluffy, about one minute. Add granulated sugar, and beat until combined. Add the egg and vanilla, and mix until combined. Add the Hungry Harry's All Purpose Flour Blend, baking powder, kosher salt, and powdered sugar.
Mix until combined.
Split dough in half and form into discs about 1" high. Wrap in parchment or wax paper and refrigerate for at least an hour.
After the dough has chilled, unwrap and lightly dust your counter and rolling pin with Hungry Harry's All Purpose Flour Blend. Preheat your oven to 350° F. Roll the dough to 1/8" thick and cut using your favorite cookie cutters. Place on a parchment lined sheet tray and bake for 8 - 10 minutes, depending on size, turning halfway through the baking process.
To assemble, first cool the cookies completely.
Once the cookies are completely cooled, make your icing. Start with half of the milk and all of the vanilla, and whisk powdered sugar into it until a thick, syrupy consistency. If the mixture gets too thick, add more milk, a few drops at a time.
Add 8 -10 drops of food coloring into the icing at various spots around the bowl. Drag a toothpick through the icing mixture, dragging the color around the icing until you have a marble effect. (See our instructional video below!)
Dip the cookies' top side into the icing, allowing the excess drip a bit before turning right side up and placing on a baking rack to dry. As needed, add more food coloring to the icing and repeat the process with the toothpick.
Once the icing is dry, serve immediately, or store in an airtight container - they'll last for 3 - 4 days.