Prep 20 mins
Cook 1 hr 30 mins
To make this lemon souffle "souffle" over the rim of the dish, use a 1-quart souffle dish and make a foil collar for it as follows: Cut a piece of foil 3 inches longer than the circumference of the souffle dish and fold it lengthwise into fourths. Wrap the foil strip around the upper half of the souffle dish and secure the overlap with tape. Tape the collar to the souffle dish as necessary to keep it from slipping. Spray the inside of the foil collar with vegetable cooking spray. When ready to serve, carefully remove the collar. For those less concerned with appearance, this dessert can be served from any 1 1/2-quart serving bowl. For best texture, serve the souffle after 1 1/2 hours of chilling. It can be chilled up to 6 hours; though the texture will stiffen slightly because of the gelatin, it will taste just as good. Cooking time is chill time.
- Place the lemon juice in a small nonreactive bowl; sprinkle the gelatin over. Set aside. Make an Ice water bath for next step.
- Heat the milk and 1/2 cup sugar in a medium saucepan over medium-low heat, stirring occasionally, until steaming and the sugar is dissolved, about 5 minutes. Meanwhile, whisk together the yolks, 2 tablespoons sugar, and cornstarch in a medium bowl until pale yellow and thickened. Whisking constantly, gradually add the hot milk to the yolks. Return the milk-egg mixture to the saucepan and cook, stirring constantly, over medium-low heat until the foam has dissipated to a thin layer and the mixture thickens to the consistency of heavy cream and registers 185 degrees on an instant-read thermometer, about 4 minutes. Pour the mixture through a mesh sieve and into a medium bowl; stir in the lemon juice mixture and zest. Set the bowl with the custard in a large bowl of ice water; stir occasionally to cool.
- While the custard mixture is chilling, in the bowl of a standing mixer fitted with the whisk attachment, beat the egg whites and cream of tartar on medium speed until foamy, about 1 minute. Increase the speed to medium-high; gradually add the remaining 2 tablespoons sugar and continue to beat until glossy and the whites hold soft peaks when the beater is lifted, about 2 minutes longer. Do not over beat. Remove the bowl containing the custard mixture from the ice water bath; gently whisk in about one third of the egg whites, then fold in the remaining whites with a large rubber spatula until almost no white streaks remain.
- In the same mixer bowl (washing is not necessary), using the whisk attachment, beat the cream on medium-high speed until soft peaks form when the beater is lifted, 2 to 3 minutes. Fold the cream into the custard and egg-white mixture until no white streaks remain.
- Pour into the prepared souffle dish (see note) or bowl. Chill until set but not stiff, about 1 1/2 hours; remove the foil collar, if using, and serve, garnishing if desired.