1 1/2 cups all-purpose flour
1/2 cup Dutch process cocoa powder
1/2 cup sugar
1/2 cup malted milk powder
1/4 tsp baking soda
1/4 tsp salt
1 tsp vanilla extract
12 tbsp unsalted butter, cut into 1/2-inch pieces, room temperature
Preheat oven to 325 degrees.
Line two cookie sheets with parchment paper; set aside.
In a large mixing bowl combine the flour, cocoa powder, sugar, malted milk powder, baking soda and salt.
With electric mixer on medium-high speed, add the vanilla then the butter, a few pieces at a time, and mix until the dough looks like wet sand and holds together when pinched; takes about 5 minutes.
Scrape the dough onto a sheet of parchment paper and pat into a 1/2-inch thick round. Cover round with another sheet of parchment paper and refrigerate approximately 10 minutes until the dough is slightly firm.
Roll out the dough between the parchment paper to 1/4-inch thick. Peel of the top sheet of the paper and cut the dough into squares or rounds using 1 1/2-inch to 2-inch cookie cutters. Reroll the scraps and repeat the process (refrigerate dough if it becomes to soft).
Place the cookies 1-inch apart on the prepared cookie sheets. Bake 8 to 10 minutes until the cookies are set and no longer shiny. Remove from oven and allow to cool on the baking sheets for 5 minutes then remove to wire racks to cool completely.
4-oz white chocolate, coarsely chopped
2 tbsp malted milk powder
pinch of salt
1/2 tsp vanilla extract
1/2 cup heavy cream
Combine the white chocolate, malted milk powder, salt, and vanilla in a large bowl.
Bring the cream to a simmer in a small saucepan over medium heat, then pour over the chocolate mixture in the bowl; stir until smooth.
Refrigerate until cold, about 25 minutes.
Beat with a mixer until thick and spreadable, about a minute.
Spread about 2 teaspoons of the filling on the underside of of half the cookies. Top with the remaining half of the cookies to form sandwich cookies.
May be stored in the refrigerator up to 5 days.