01 - Preheat oven to 300°F. Line a baking sheet with parchment paper.
02 - In a clean mixing bowl, beat egg whites and cream of tartar with an electric mixer until soft peaks form. Gradually add sugar, beating until stiff, glossy peaks develop.
03 - In a separate bowl, whisk together egg yolks, cornstarch, and vanilla extract until smooth.
04 - Gently fold egg yolk mixture into whipped egg whites, maintaining aeration.
05 - Divide batter into four separate bowls. Add a few drops of gel food coloring to each bowl and gently fold until evenly colored.
06 - Spoon colorful dollops side by side onto prepared baking sheet to create a rainbow presentation. Swirl gently with spatula if desired.
07 - Bake for 25 minutes, or until set and lightly golden.
08 - Allow cloud bread to cool slightly before removing from baking sheet. Serve immediately for optimal fluffiness.