Preheat the oven to 300°F (150°C). Separate the egg whites from the yolks and place the whites in a mixing bowl.
Beat the egg whites on medium speed until frothy. Gradually add the sugar, a little at a time, beating until fully incorporated.
Sift the cornstarch into the bowl and beat until combined. Increase speed to high and continue beating for 2 to 3 minutes until stiff peaks form and the mixture resembles shaving cream.
Line a sheet pan with parchment paper or a silicone baking mat. Spread the meringue onto the pan and shape it into a loaf using a spatula.
Bake on the middle rack for 35 to 45 minutes until golden brown and a wooden skewer inserted in the center comes out clean. Allow to cool completely before slicing with a serrated knife or tearing apart to serve.
Notes
Tip 1: For best results, ensure the bowl and beaters are completely clean and free of grease before whipping egg whites.
Tip 2: Store cloud bread in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days.
Tip 3: You can substitute sugar with an equal amount of powdered erythritol for a lower-carb version.
Tip 4: To speed up cooling, place the baked cloud bread on a wire rack and let it cool completely before cutting.
Tip 5: Cloud bread pairs well with cream cheese, avocado, or smoked salmon for a savory snack.