3 envelopes hot chocolate powder without marshmallows (1.38 ounce pouches)
1 tsp. instant espresso powder
1 tsp. baking powder
1 tsp. baking soda
1/4 tsp. salt
1 cup salted butter, room temperature
1 3/4 cups sugar
2 large eggs
2 tsp. vanilla extract
1 1/2 cups white chocolate chips
24 marshmallows, cut in halved crosswise
Instructions
Add a few inches of water to a saucepan and heat over low heat until simmering. Add the chopped chocolate to a heatproof bowl and set over the saucepan. Let melt, 3 to 4 minutes, then stir until smooth. Remove the bowl from the pan and let cool slightly.
In a medium bowl, whisk together the flour, malted milk powder, hot cocoa mix, espresso powder, baking powder, baking soda, and salt to combine and get rid of any lumps.
In a large bowl, beat the butter and sugar with an electric mixer on medium-high speed until light and smooth, 2 to 3 minutes. Add the eggs, one at a time, and beat until combined. Beat in the vanilla. With the mixer on low speed, gradually add the melted chocolate. Increase the speed to medium-high and beat until smooth and light, about 1 minute. With the mixer on low speed, add the flour mixture and beat until just combined, 30 seconds to 1 minute. Stir in the white chocolate chips. Cover the dough and refrigerate until it just begins to firm up, about 30 minutes.
Preheat the oven to 350°F. Line 2 baking sheets with parchment paper. Scoop the dough into balls (about 1 tablespoon each) and place on the baking sheets, about 2 inches apart. Bake until the edges just begin to set, 9 to 10 minutes.
Remove from the oven and place a marshmallow half on the center of each cookie, cut-side down. Continue baking until the edges of the cookies are set and the marshmallows are stuck to the cookie, 2 to 3 minutes more. Let cool 5 minutes on the pans; remove to racks to cool completely.
