Rainbow Cookies

Preheat an oven to 350°F (180°C). Spray 3 quarter baking sheets, each 9 by 13 inches (23 by 33 cm), with nonstick cooking spray, line with parchment paper and spray the parchment.

In a bowl, stir together the flour, salt and baking powder. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, combine the almond paste and butter. Beat on high speed until smooth, about 1 minute. Add 1 cup (8 oz./250 g) of the sugar, the egg yolks, and the vanilla and almond extracts. Beat on high speed until light and fluffy, about 4 minutes, scraping down the sides of the bowl as needed.

Add half of the flour mixture to the sugar mixture and beat on medium speed until no dry streaks remain. Repeat with the second half of the flour mixture. Transfer the mixture to a large bowl.

Wash and dry the bowl of the stand mixer and switch to the whisk attachment. Add the egg whites to the bowl and beat on high speed until the mixture is foamy and starting to thicken, about 30 seconds. Add the remaining 2 Tbs. sugar and continue beating until stiff peaks form, about 30 seconds more.

Using a rubber spatula, fold the egg whites into the batter until just combined.
 
Transfer a third of the batter to one of the prepared baking sheets and, using an offset spatula, spread into an even layer. Set aside.

Transfer another third of the batter to another bowl and add the dried raspberries. Stir until combined and the mixture is a uniform pink color. Transfer to another of the prepared baking sheets and spread in an even layer. Set aside.

Add the matcha powder to the batter remaining in the bowl. Stir until combined and the mixture is a uniform light green color. Transfer to the last prepared baking sheet and spread in an even layer.

Transfer the pans to the oven and bake until the tops are just set and the edges are barely browned, 10 to 12 minutes. Transfer the pans to a wire rack and let cool completely.

Line a baking sheet (about 13 by 18 inches/33 by 45 cm) with parchment paper. Invert the green cake layer onto the baking sheet and peel off the parchment.

In a small bowl, combine the raspberry preserves with 2 tsp. water and whisk until combined. Spread half of the raspberry mixture evenly over the green cake layer.

Carefully turn out the white cake layer on top of the green cake layer and peel off the parchment. Spread evenly with the remaining raspberry mixture, then turn out the pink cake layer on top and peel off the parchment paper.

Wrap the baking sheet with the cake layers on top in plastic wrap, then place another rimmed baking sheet on top of the cake layers. Weigh down the top baking sheet with a heavy cutting board or a few cans. Refrigerate for at least 4 hours or up to overnight.

Place half of the chocolate in a microwave-safe bowl and microwave for 30 seconds. Stir to combine and repeat until the chocolate is melted and smooth.

Remove the cake from the refrigerator and unwrap. Using an offset spatula, spread the melted chocolate on the top, going all the way to the edges. Refrigerate, uncovered, until firm, about 1 hour.

Melt the remaining half of the chocolate in the same way as above.

Carefully invert the cake onto a cutting board, chocolate side down, and spread the remaining chocolate to the edges of the cake. Return to the refrigerator, uncovered, until the chocolate just begins to firm up but does not harden completely, about 10 minutes.

To cut, run a sharp knife under hot water and dry off with a kitchen towel. Trim the edges of the cake to create clean, straight edges. Cut the cake into 24 squares, each about 2 inches (5 cm) square, running the knife under hot water and drying it off between each cut.

Return the cookies to the refrigerator until the chocolate is firm, about 30 minutes.

Serve immediately or transfer the cookies to an airtight container in a single layer. Store at room temperature for up to 2 days, or refrigerate for up to 1 week. Makes 24 cookies.

Williams Sonoma Test Kitchen