Malted White Chocolate Sandwich Cookies with Halva Buttercream

Make the shortbread cookies:

1. In a medium size bowl, whisk the flour, malted milk powder, white chocolate powder, and salt to combine.
2. In the bowl of a standing mixer fitted with the paddle attachment, beat the butter, sugar, and vanilla until the mixture is light and fluffy, about 2 minutes. Stir in the flour mixture, mixing just long enough to combine.
3. Dump the dough out onto a clean work surface and divide in half. Working with one half at a time, place half the dough in-between two sheets of wax paper and cover the other half with plastic wrap to keep it from drying out. Roll out each portion of dough between two sheets of wax paper until the dough is flattened into an ⅛ inch thick disc. Stack discs, with wax paper between them, on a cookie sheet and refrigerate for at least 30 minutes and up to 24 hours.
4. When you are ready to bake the cookies, preheat the oven to 350, line a baking sheet with parchment paper, and remove one disc of dough from the refrigerator to a flat work surface. Cut out cookies using a biscuit cutter and lay each carefully onto the prepared baking sheet. They will not spread, so you can place them within a ½ inch of each other on the baking sheet.
5. Bake cookies in the center of the oven for 7 minutes. Let cool for 2-3 minutes on the baking sheet before removing cookies to a wire rack to cool completely. Repeat with the remaining dough, scooping up scraps and re-rolling. If the dough gets too soft to work with, simply return it (covered) to the refrigerator for a few minutes to harden.

Make the halva buttercream:

1. Blend the halva in a food processor for 1-2 minutes. Add white chocolate, and pulse to mix.
2. Add the butter and sugar to the bowl of a standing mixer and beat until very light and fluffy - about 4 minutes. Scrape down the sides of the bowl. Add the halva mixture, vanilla, and salt and beat on high for 1 minute longer.
3. Refrigerate the frosting in an airtight container until firm enough to pipe. The frosting can be stored in the refrigerator for up to 5 days.

Fill and decorate the cookies:

1. Fit a pastry bag with a star tip and fill with the halva frosting. Pipe filling on the flat side of one of the cookies and top with a second cookie. Repeat with remaining cookies. Be generous with the amount of frosting. (You can also spread a thick layer of frosting with a small knife.)
2. Place the cookies on a wire rack or a long sheet of parchment paper.
3. Melt the white and dark chocolate chips by placing them in separate bowls and microwaving them in 30 second intervals at half power, stirring frequently.
4. Add the chocolates to separate pastry bags and clip the tip of the bags to create a tiny hole from which to drizzle the chocolate. Drizzle the chocolates over the cookies in whatever decorative pattern you like.