1-Prep Work and Mise en Place: First, gather all ingredients and make sure your egg is at room temperature. Line baking sheets with parchment paper and pre-measure the granulated sugar used for rolling. Chilling the dough is a required step for texture, so plan for at least 2 hours of chill time.

2-First Step: Creaming the Butter and Sugars: Beat the 1/2 cup (8 Tbsp; 113g) unsalted butter, 1/2 cup (100g) granulated sugar, and 1/2 cup (100g) packed light or dark brown sugar together until the mixture is fluffy and light in color, about 3 minutes. Use a hand mixer or stand mixer on medium speed. Add the 1 large egg and 1 teaspoon pure vanilla extract, beating until combined.

3-Second Step: Mixing the Dry Ingredients: In a separate bowl, whisk together 1 and 1/4 cups (156g) all-purpose flour, 1/2 cup (45g) natural unsweetened cocoa powder, 1 teaspoon baking soda, and 1/8 teaspoon salt. This ensures even distribution so your cookies bake uniformly.

4-Third Step: Combine Wet and Dry: Slowly add the dry ingredients to the wet ingredients on low speed to avoid a cloud of cocoa and flour. Once mostly combined, increase speed slightly and beat in 2 teaspoons (10ml) milk (dairy or nondairy). The dough will be thick and sticky, which is normal.

5-Fourth Step: Chill the Dough: Cover the cookie dough and chill in the refrigerator for at least 2 hours and up to 3 days. Chilling is important for managing the sticky dough and for achieving the right texture. If you are short on time, a minimum of 2 hours is recommended, but longer chilling improves flavor meld and shape.

6-Fifth Step: Shape and Sugar-Coat: When ready to bake, preheat your oven to 350°F (177°C). Line baking sheets with parchment paper. Scoop and roll dough into 1 heaping tablespoon balls this recipe yields about 22 to 24 cookies. Roll each ball thickly in 1/2 cup (100g) granulated sugar, then place them 2 to 3 inches apart on the baking sheets. The sugar coating creates a sparkly, crackled finish on the cookie tops.

7-Sixth Step: Bake: Bake for 10 to 12 minutes, until the edges are set. If the cookies have not spread by about 9 minutes, lightly bang the baking sheet on the counter 2 to 3 times to encourage spreading, then continue baking. This little trick helps the cookies open up without overbaking.

8-Seventh Step: Add Andes Mints: Cool the cookies on the baking sheet for 2 minutes. Immediately press one chocolate mint into the center of each warm cookie. Let the topping melt for 5 minutes, then gently swirl it with a knife or spatula for a pretty frosting-like finish. The melted mint sets to a matte look in less than an hour.

9-Final Step: Cool and Store: Transfer the cookies to a cooling rack to cool completely. Store leftover cookies covered at room temperature up to 1 week. For longer storage, freeze baked cookies or unbaked dough balls for up to 3 months.