Creating perfect meringue nests requires both technique and stabilizers to prevent the dreaded cracks. Add superfine sugar gradually - one tablespoon at a time - beating well between additions to create stable structure. The secret weapons are white vinegar and cornstarch folded in at the end: vinegar creates slight acidity that stabilizes proteins, while cornstarch absorbs moisture that could cause cracking. Bake low and slow at 200°F, never opening the oven door during the first 2 hours. Cool gradually in the turned-off oven with door slightly ajar.