Step 1: Preheat your oven to 300°F (150°C) and line a baking sheet with parchment paper. Ensure your mixing bowl is completely free of grease.
Step 2: Place the egg whites and a pinch of salt in the bowl and begin whisking on low speed until the mixture becomes frothy.
Step 3: Add the cream of tartar to the frothy whites and increase the mixer speed to medium. Continue whisking until soft peaks form.
Step 4: Gradually add the sugar one tablespoon at a time, whisking constantly on high speed until the whites are thick, glossy, and hold stiff peaks.
Step 5: Gently fold in the vanilla extract and cornstarch using a spatula, being careful not to deflate the air you have incorporated.
Step 6: Mound the mixture onto the prepared baking sheet, shaping it into a round loaf or individual clouds.
Step 7: Bake for 30-35 minutes until the outside is slightly golden and firm to the touch. Let cool completely before serving.