Note: This cookie dough requires at least 2 hours of chilling, but ideally overnight for best results. The cookies will be thicker the longer they chill (up to 3 days).
In a medium bowl, whisk the flour, cocoa powder, instant espresso, baking soda, and salt together until combined
1 cup all-purpose flour, 2/3 cup natural unsweetened cocoa powder, 2 Tablespoons instant espresso powder, 1 teaspoon baking soda, 1/2 teaspoon kosher salt
In a separate large bowl using an an electric mixer or stand mixer fitted with a paddle attachment, beat the butter, granulated sugar, and brown sugar on medium-high speed for 2-3 minutes.
1/2 cup unsalted butter, 1/2 cup granulated sugar, 1/2 cup light brown sugar
Add the egg, vanilla extract, rum extract, and milk and beat until light and fluffy, 1-2 minutes, scraping down the sides and bottom of the bowl as needed.
1 large egg, 1 teaspoon vanilla extract, 1 1/2 teaspoons rum extract, 1 Tablespoon milk
Turn the mixer down to low speed and slowly add the dry ingredients into the wet ingredients until combined.
Cover with plastic wrap and chill for at least 2 hours or up to 3 days. Do not skip this step (it prevents them from spreading).
Preheat the oven to 350°F and line two large baking sheets with parchment paper. If the dough was chilling for longer than 24 hours, allow it to soften at room temperature for 15-30 minutes for easier scooping.
Using a medium cookie scoop (about 3Tablespoons), scoop the cookie dough and drop them 2-3 inches apart on the prepared baking sheet. The dough will be sticky. Wet your hands slightly to prevent sticking if needed.
Bake the cookies in the preheated oven for 10-12 minutes or until the edges are set and the tops look slightly soft. Cool the cookies for 5 minutes on the cookie sheet then transfer them to a cooling rack to cool completely.
While they’re cooling, add the white chocolate to a microwave safe bowl. A taller container, like a liquid measuring cup is best. Microwave in 30 second increments, stirring between each, until it's melted and smooth.
10-12 ounces premium white chocolate
Dip half of each cookie in the melted white chocolate then place it on a piece of parchment paper. Garnish with 1-3 coffee beans. Let them set at room temperature or place them in the freezer for a few minutes to set the chocolate. Baked cookies stay fresh in an airtight container at room temperature for 5 days or can be frozen for up to 3 months.