Instructions

• Line two baking sheets with parchment paper and set aside.
• In a large bowl (or the bowl of a stand mixer) cream 12 tablespoons unsalted butter, softened, with a hand mixer or paddle attachment until light and fluffy.
• Add 2 large eggs and 1 teaspoon vanilla extract to the butter and mix until combined.
• In a medium bowl, whisk together 2¼ cups all-purpose flour, ¾ cup powdered sugar, ¼ teaspoon baking powder, and ¼ teaspoon kosher salt.
• Gradually add the dry mixture to the butter mixture and mix on low speed until the dough just comes together.
• Lightly flour your work surface. Turn the dough out onto the floured surface and knead briefly by hand until smooth and uniform.
• Using a floured rolling pin, roll the dough to about 1/4 inch thickness.
• Use a small round cookie cutter to cut out an even number of cookies. Transfer the cut cookies to the prepared baking sheets, spacing them about 1 inch apart.
• Chill the prepared cookie rounds on the baking sheets in the refrigerator for 30 minutes. While they chill, preheat your oven to 350°F.
• Bake the chilled cookies at 350°F for 15–18 minutes, or until the edges are lightly golden. Remove from the oven and cool completely on a wire rack before assembling.
• Make the chocolate filling: place ¾ cup semi-sweet chocolate chips and 1 tablespoon unsalted butter in a microwave-safe bowl. Microwave in 20-second intervals, stirring between intervals, until smooth and fully melted. Let cool slightly until spreadable.
• Spread a thin layer of the melted semi-sweet chocolate onto the flat side of half of the cooled cookies. Top each with a remaining cookie to form a sandwich. Press gently to seal.
• Place the sandwich cookies on a baking sheet and refrigerate or leave at room temperature until the semi-sweet chocolate filling is set (about 10–15 minutes).
• Melt the white chocolate coating: place 2½ cups white chocolate candy coating in a microwave-safe bowl and microwave in 20-second intervals, stirring between intervals, until smooth and fully melted.
• If using the optional colored candy coating (½ cup), melt it in a separate microwave-safe bowl in 20-second intervals until smooth. Transfer the melted colored coating to a small piping bag or a resealable plastic bag and snip a tiny corner for drizzling.
• Dip each sandwich cookie into the melted white chocolate coating (or spoon the coating over the top), letting excess drip off, and return to parchment-lined baking sheets.
• Immediately drizzle the melted colored candy coating over the white-coated cookies, if using.
• Allow the coatings to set completely at room temperature or speed up setting in the refrigerator. Once set, dust the cookies with additional powdered sugar, if desired.