Technicolor Cookies

Make the cookies: In a medium bowl, whisk together flour, cinnamon, ginger, cardamom, baking powder and salt.

In a large bowl using an electric mixer on medium speed, beat together butter, granulated sugar, orange zest, vanilla extract and egg. Add flour mixture to butter mixture, and beat until combined.

Set a 12-by-16-inch sheet of parchment paper on a work surface. Set the dough on top and cover with another piece of parchment. Roll dough into an even ¼-inch-thick rectangle, squaring off the edges. Set the dough, still sandwiched in parchment, on a rimmed baking sheet and refrigerate until very cold and firm, about 30 minutes.

Prepare the royal icing: Combine powdered sugar and meringue powder in a large bowl. Add 2/3 cup water and beat with an electric mixer on medium until thick and glossy, about 7 minutes. Check the consistency of the icing: When you drizzle the icing over itself, it should take 10 seconds to reincorporate. Add more water, 1 teaspoon at a time as necessary, to reach that consistency.

Separate icing into 5 bowls and tint 4 as desired, leaving one white. Cover and let stand at room temperature for 30 minutes.

Heat oven to 350 degrees. Line 2 baking sheets with parchment paper.

Pull the dough from the fridge, and, working quickly, cut dough into 1-by-2 1/2-inch rectangles. If dough is still cold, separate rectangles and place on prepared baking sheets ¼ inch apart. If the dough has gotten warm, chill (or freeze) it until cold before baking.

Bake, rotating halfway through, until golden brown, 10 to 12 minutes. Transfer cookies to a rack to cool completely, about 30 minutes. Set the rack over a parchment-lined sheet and line up the cookies, sides touching, in rows of 8.

Set another rack over a parchment- lined sheet. Into a small (4-inch- diameter) bowl, spoon some of each color so you have several parallel bands of colored icing. (Cover any unused icing.) Pour icing in thin ribbons over the cookies moving left to right, then right to left and back again, filling in holes, until you run out. Repeat with more icing. Immediately and carefully separate cookies, one by one, with an offset spatula and transfer to the clean rack.

Let the cookies stand at room temperature, uncovered, until set, at least 6 hours.