Rainbow Icebox Cake with Homemade Chocolate Cookies
Author: 
Yield: 12 servings
 
Ingredients
For the Rainbow Whipped Cream
  • 3 cups (720 ml) heavy whipping cream, very cold
  • ¾ cup (170 g) crème fraîche
  • ¾ cup (150 g) granulated sugar
  • 2 teaspoons pure vanilla paste
  • 6 rainbow colors of food gel
For the Chocolate Cookies
  • 10½ ounces (22⁄3 sticks/300 g) unsalted butter, softened
  • 1½ cups (300 g) granulated sugar
  • 1 large egg yolk
  • 1 tablespoon pure vanilla extract
  • 11⁄3 cups (115 g) unsweetened cocoa powder
  • ½ teaspoon kosher salt
  • ¼ teaspoon baking powder
  • 2½ cups (315 g) all-purpose flour
For the Assembly
  • 1 cup (240 ml) heavy whipping cream, very cold
  • 1 tablespoon granulated sugar
  • Rainbow sprinkles (optional)
Instructions
Make the Rainbow Whipped Cream
  1. Chill the bowl and whisk attachment of a standing mixer in the refrigerator for 10 minutes.
  2. Put the cream and crème fraîche into the chilled bowl of the stand mixer and whisk on low for 1 minute.
  3. With the mixer running, stream in the sugar and vanilla paste.
  4. Increase the speed to medium-high and continue whisking.
  5. Stop the mixer before soft peaks form; it’s important not to overwhip the cream at this stage. (The thickened cream should stream off the whisk but still pile softly back into the bowl; the whisk will leave faint streaks in the cream that will smooth out fairly quickly.)
  6. Line a colander with one layer of cheesecloth and place the colander in a bowl.
  7. Pour the partially whipped cream into the colander and place the bowl in the refrigerator for at least 3 hours.
  8. The cream should be thick enough to remain in the colander, but not so thick that any additional whipping will take it past soft peaks.
Make the Chocolate Cookies
  1. In the bowl of a standing mixer fitted with the paddle attachment, beat the butter and sugar at low speed until smooth.
  2. Beat in the egg yolk and vanilla.
  3. Scrape down the sides of the bowl and the paddle.
  4. Add the cocoa powder, salt, and baking powder and beat until combined.
  5. Scrape down the bowl again.
  6. Add the flour and beat just until combined.
  7. Form the cookie dough into four disks, wrap each in plastic wrap, and refrigerate for about 1 hour, or until firm.
  8. Preheat the oven to 350°F (175°C).
  9. Line two baking sheets with parchment paper.
  10. On a lightly floured board, roll out a disk of chilled cookie dough into a 12-inch (30.5-cm) round 8 inch (3 mm) thick.
  11. Using a 2-inch (6-cm) round biscuit cutter, stamp out as many rounds of dough as you can; transfer the rounds to the prepared baking sheets.
  12. Repeat with a second disk.
  13. Quickly gather the dough scraps, reroll, and stamp out more cookies.
  14. Bake the chocolate cookies until they are dry and set, 8 to 10 minutes.
  15. Transfer the pans to a wire rack to cool for 10 minutes, then transfer the chocolate cookies directly to the rack to cool completely.
  16. Repeat the rolling, stamping, and baking process with the remaining dough disks.
  17. You should have 60 to 75 finished cookies in total.
Finish the Rainbow Whipped Cream
  1. Put ¼ cup of the refrigerated whipped cream into a small bowl and set aside.
  2. Evenly divide the remaining whipped cream into six medium bowls.
  3. Add a different food gel, a drop or two at a time, to each of the six bowls, then fold each with a rubber spatula until incorporated and the desired color is reached. (As you fold the whipped cream, it will get stiffer; do not fold too much or it could become overwhipped.)
  4. If needed, whisk each bowl of colored whipped cream a few more times by hand to reach soft peaks.
  5. Do not overwhip.
Assemble the Rainbow Icebox Cake
  1. Arrange 7 cookies on a platter in a 7- to 8-inch (17- to 20-cm) circle (side by side, with one cookie in the middle—do not overlap).
  2. Dollop the first color of whipped cream (in this case, red) gently over the cookie layer.
  3. Spread the whipped cream with an offset spatula to the very edge of the cookies.
  4. Top the whipped cream with another layer of cookies, offset from the first layer.
  5. Repeat the process, filling in any blank spots in the layers with broken cookie pieces and using the whipped cream in rainbow order.
  6. Top the last layer of cookies with the reserved ¼ cup of plain whipped cream, spreading in a thin layer to help soften the top layer of cookies.
  7. Place the cake, loosely covered, in the refrigerator overnight to set.
  8. The next day, chill the bowl and whisk attachment of a standing mixer in the refrigerator for 10
  9. minutes.
  10. Put the cream in the chilled bowl of the stand mixer and whisk on low speed for 1 minute.
  11. With the mixer running, stream in the sugar.
  12. Increase the speed to medium-high and continue whisking just until soft peaks form.
  13. Remove the cake from the refrigerator and top it with a big pile of the white whipped cream, completely covering the thin layer of whipped cream.
  14. Cover loosely in plastic wrap or invert a glass or plastic container over the cake and refrigerate for at least 30 minutes.
  15. Sprinkle with rainbow sprinkles just before serving, if desired.
Notes
How to store: Store leftovers in the refrigerator, covered, for up to 1 day. You might have leftover cookies—we always like to have a few extra on hand in case a few crumble or break; you can snack on the rest or store, tightly covered, for up to 4 days.
Recipe by Baked Sunday Mornings at http://bakedsundaymornings.com/2015/05/28/in-the-oven-rainbow-icebox-cake-with-homemade-chocolate-cookies/