Step 1: Brine the Orange Zest (Optional but Recommended). Combine the dill pickle brine and water in a small bowl. Add the orange zest and let it sit while you prepare the rest of the components.

Step 2: Cream Butter, Sugar, and Zest. Combine the softened butter, granulated sugar, and drained orange zest in the bowl of an electric mixer. Beat on medium speed until smooth.

Step 3: Add Eggs and Vanilla. Add the eggs and vanilla. Beat again, scraping down the sides of the bowl halfway through.

Step 4: Sift Dry Ingredients. Sift together the flour, baking powder, and salt into a separate bowl.

Step 5: Combine Wet and Dry Ingredients. With the mixer on low speed, add the dry ingredients to the butter mixture, alternating with the milk, until the dough comes together.

Step 6: Chill Dough. Divide the dough in half, then flatten both halves into disks and place them in separate resealable plastic bags. Refrigerate the dough until firm, about 2 hours.

Step 7: Preheat Oven and Prepare Baking Sheets. Preheat the oven to 350°F (175°C). Line 2 baking sheets with parchment paper.

Step 8: Roll and Cut Cookies. Roll out both pieces of dough until about ¼ inch thick and cut out as many cookies as you can with 2- to 3-inch butterfly cookie cutters.

Step 9: Bake. Place the cookies on the prepared baking sheets and bake until they’re just set but not browned, 8 to 10 minutes.

Step 10: Cool. Remove from the oven and let cool 5 minutes on the baking sheets, then remove to racks to cool completely before decorating.

Step 11: Make the Icing. Combine the powdered sugar, milk, and egg whites in the bowl of an electric mixer and beat on medium-high speed until thick and glossy. Add more powdered sugar if the icing seems too thin. Just play with it until it’s right. The icing should be stiff enough to dip the top side of the cookie and get a thick, even layer.

Step 12: Divide and Color Icing (and Add Pickle Flavor). Divide most of the icing among 3 or 4 smaller bowls. Add 2 to 3 drops each of red and orange food coloring to each bowl, scattering it over the surface of the icing. Drag a toothpick through the drops a few times to make swirls. Place the reserved uncolored icing in another bowl and add the dill pickle powder. Mix thoroughly.

Step 13: Dip Cookies. Dip the top side of some each cookie in the pickle-powdered icing and let the excess drip off, then let dry on a rack. Dip the remaining cookies in the colored icing.

Step 14: Dry Completely. Let the icing dry completely, about 1 hour. Sprinkle with a tiny amount of finely chopped fresh dill, if desired, after the icing has dried.