Frozen Rainbow Chiffon Cake

INGREDIENTS

• Vegetable oil cooking spray
• 1 1/2 cups blackberries (6 ounces)
• 1 1/4 cups blueberries (6 ounces)
• 1/2 cup plus 2 tablespoons fresh lemon juice (from 4 to 5 lemons)
• 10 large egg whites, room temperature
• Salt
• 2 3/4 cups plus 1 tablespoon sugar
• 3/4 cup plus 3 tablespoons water
• 2 ripe papayas, peeled and seeded
• 3 kiwifruits, peeled
• 1 cup strawberries (6 ounces), hulled
• 1 1/4 cups raspberries (6 ounces)
• 1 can (15 ounces) apricots in juice, drained
• Seven-Minute Frosting (recipe follows) Seven-Minute Frosting

COOK'S NOTE

Fruit purees can be refrigerated for up to 2 days; frosted cake can be frozen overnight. Food-safety note: The egg whites in this cake are not fully cooked.

DIRECTIONS

1. STEP 1

   Coat two 8-inch springform pans with cooking spray. Line sides with parchment, leaving a 2-inch collar extending over top.

2. STEP 2

   Puree blackberries, blueberries, and 2 tablespoons lemon juice in a blender until smooth. Strain through a fine sieve; discard solids.

3. STEP 3

   Whisk 2 egg whites and a pinch of salt with a mixer on medium speed until foamy. Meanwhile, combine 1/2 cup plus 1 tablespoon sugar with 3 tablespoons water in a small saucepan over medium-high heat, stirring until sugar dissolves. Cook until syrup reaches 250 degrees on a candy thermometer. Immediately add sugar syrup in a slow, steady stream down the side of the bowl. Raise speed to high, and whisk until thick, shiny, and cooled, about 7 minutes. Whisk in berry puree. Pour mixture into 1 pan, and freeze until firm, about 2 hours.

4. STEP 4

   Meanwhile, puree papayas and 2 tablespoons lemon juice in a blender until smooth. Strain.

5. STEP 5

   Repeat step 3 with 2 egg whites, a pinch of salt, 1/2 cup plus 1 tablespoon sugar, and 3 tablespoons water, whisking in papayapuree. Pour mixture into remaining pan, and freeze until firm, about 2 hours.

6. STEP 6

   Puree kiwifruits and 2 tablespoons lemon juice in a blender until smooth. Strain.

7. STEP 7

   Repeat step 3 with 2 egg whites, a pinch of salt, 1/2 cup plus 1 tablespoon sugar, and 3 tablespoons water, whisking in kiwifruit puree. Pour mixture onto froze
   n berry layer, and freeze until firm, about 2 hours.

8. STEP 8

   Meanwhile, puree strawberries, raspberries, and 2 tablespoons lemon juice in a blender until smooth. Strain.

9. STEP 9

   Repeat step 3 with 2 egg whites, a pinch of salt, 1/2 cup plus 1 tablespoon sugar, and 3 tablespoons water, whisking in strawberry-raspberry puree. Pour mixture onto frozen papayalayer, and freeze until firm, about 2 hours.

10. STEP 10

    Puree apricots and 2 tablespoons lemon juice in a blender until smooth. Strain.

11. STEP 11

    Repeat step 3 with 2 egg whites, a pinch of salt, 1/2 cup plus 1 tablespoon sugar, and 3 tablespoons water, whisking in apricotpuree. Pour mixture onto frozen kiwi layer, and freeze until firm, about 2 hours.

12. STEP 12

    Release sides of pans; carefully transfer papaya and strawberry-raspberry layer cake onto apricot layer. Freeze cake while you make the frosting.

13. STEP 13

    Remove parchment paper. Frost top and sides of cake. Freeze until ready to serve.