The soufflé — both savoury and sweet — requires a base flavour (pastry cream for sweet soufflés, thick béchamel for savoury) folded into beaten egg whites, then baked in a buttered, sugared mold. The rise occurs because air bubbles trapped in the beaten whites expand in the oven heat — and the rise falls because those bubbles burst or contract as the soufflé cools. The soufflé's reputation for temperament is earned.
- **The base:** Must be flavour-concentrated — it will be diluted by the egg whites. A soufflé base that tastes barely correct before the whites are added will be barely perceptible in the finished soufflé. - **The egg whites:** Beaten to soft-to-medium peaks — not stiff. Stiff whites do not fold smoothly into the base and produce a dry, streaky soufflé. Soft-medium peaks fold in smoothly, producing an even, airy result. - **The fold:** One-third of the whites beaten vigorously into the base (to lighten it); the remaining two-thirds folded gently with a wide spatula — cutting down through the centre and sweeping up from the bottom. - **The mold preparation:** Buttered and sugared (sweet) or buttered and Parmigiano-dusted (savoury) — the coating provides the first surface the soufflé touches, determining how evenly it rises. - **No opening the oven:** For the first two-thirds of baking time — the temperature drop from opening causes immediate deflation. Decisive moment: The fold completion — when the whites and base are just combined, with one or two white streaks still visible. Under-folded: white streaks visible throughout; the white bands don't rise evenly. Over-folded: the whites have lost their air and the soufflé will not rise adequately.
The Complete Robuchon