The sweet soufflé is a leavened egg-foam dessert that relies on the rapid expansion of trapped air and steam within a stabilized meringue to achieve its dramatic rise. The base — a crème pâtissière or bouillie (flour-thickened flavour base) — is prepared first, enriched with egg yolks, and flavoured with fruit purée, chocolate, liqueur, or vanilla. A standard base uses 250 ml milk, 50 g sugar, 30 g flour, and 3 yolks. Separately, 4-5 egg whites are whipped with a tablespoon of sugar to medium-firm peaks. One-third of the meringue is folded vigorously into the warm base to lighten it — this sacrificial portion reduces the viscosity gap between the two components. The remaining meringue is folded in two additions with a spatula, using broad, gentle strokes that preserve as much air as possible. The prepared ramekins — brushed with soft butter in upward strokes and coated evenly with caster sugar — provide the friction surface the batter needs to climb. The batter is filled to just below the rim, levelled with a palette knife, and a thumb run around the inside edge creates a shallow groove that encourages a uniform top-hat rise. Baking at 190-200°C for 12-14 minutes for individual 180 ml ramekins causes the air cells to expand and the egg proteins to set into a fragile scaffold. The soufflé must be served within 60-90 seconds of leaving the oven — the scaffold is stabilized only by the heat; as it cools, steam condenses and the structure collapses. A properly baked soufflé should rise 5-7 cm above the rim, have a golden crust, and reveal a barely set, creamy centre when opened.
Prepare a flavourful, well-seasoned base — the base must be slightly over-flavoured since dilution by meringue reduces intensity by 40-50%; butter and sugar ramekins with upward strokes to provide climbing grip; fold meringue in three stages — one-third vigorously, the rest gently; bake at 190-200°C without opening the oven door; serve within 90 seconds of removing from the oven.
Assemble the soufflé batter and hold it in buttered, sugared ramekins in the freezer for up to 2 hours before baking — add 2-3 minutes to baking time; a chocolate soufflé base benefits from an extra yolk for richness without compromising structure; place ramekins on a preheated baking sheet to give bottom heat that accelerates the initial rise; table-side, pierce the centre with a spoon and pour in crème anglaise for a sauce-from-within presentation.
Using a base that is too thick, which weighs down the meringue and limits rise; over-whipping whites to stiff peaks, making them difficult to fold and creating a dry, cracked top; buttering ramekins in random directions or leaving bare spots, causing the soufflé to stick and rise unevenly; opening the oven door during the first 10 minutes, causing the fragile foam to collapse from thermal shock; under-flavouring the base, resulting in a bland soufflé despite proper technique.
Escoffier, Le Guide Culinaire; Roux Brothers, New Classic Cuisine; Hermé, Larousse des Desserts