01 - Preheat oven to 300°F and line a baking sheet with parchment paper.
02 - Using a clean bowl, beat egg whites and cream of tartar on medium-high speed until soft peaks form. Gradually incorporate sugar, continuing to beat until mixture is stiff and glossy.
03 - In a separate bowl, whisk together egg yolks, cornstarch, and vanilla extract until the mixture becomes smooth.
04 - Gently fold the blended yolk mixture into the whipped egg whites, ensuring minimal deflation for optimal volume.
05 - Evenly divide batter into individual bowls according to your chosen colors. Add a few drops of gel food coloring to each and gently fold until the color is evenly distributed.
06 - Spoon colored batter portions onto the prepared baking sheet side by side to form a rainbow pattern. For a marbled effect, swirl gently with a spatula.
07 - Transfer to the oven and bake for 25 minutes until set and lightly golden.
08 - Allow cloud bread to cool briefly on the baking sheet before serving. Enjoy immediately for maximum fluffiness.