- 1/4 cup lemon juice from 1 or 2 lemons
- 1 1/4 teaspoons grated lemon zest (grate before juicing)
- 1 teaspoon gelatin , unflavored
- 1/2 cup whole milk
- 1/3 cup granulated sugar
- 3 large egg whites at room temperature, less one tablespoon
- 1 large egg yolk , at room temperature
- 1/8 teaspoon cornstarch
- 1/3 cup heavy cream
- Pinch cream of tartar
- fresh mint leaves , raspberries, confectioners' sugar, or finely chopped pistachios for garnish (optional)
1. Place lemon juice in small nonreactive bowl; sprinkle gelatin over. Set aside.
2. Heat milk and two tablespoons sugar in small saucepan over medium-low heat, stirring occasionally, until steaming and sugar is dissolved, about 3-4 minutes. Meanwhile, whisk together yolks, 1 tablespoon sugar, and cornstarch in medium bowl until pale yellow and thickened, 3 to 5 minutes. Whisking constantly, gradually add hot milk to yolks. Return milk and egg mixture to saucepan and cook, stirring constantly, over medium-low heat until foam has dissipated to a thin layer and mixture thickens to consistency of heavy cream and registers 185 degrees on instant-read thermometer, about 2-3 minutes. Strain into medium bowl; stir in lemon juice mixture and zest. Set bowl of custard in large bowl of ice water; stir occasionally to cool.
3. While custard mixture is chilling, with hand mixer beat egg whites and cream of tartar in medium mixing bowl on medium-high speed until foamy, about 1 minute. Increase speed to high; gradually add remaining sugar and continue to beat until glossy and whites hold soft peaks when beaters are lifted, about 2 minutes longer. Do not overbeat. Remove bowl containing custard mixture from ice water bath; gently whisk in about 1/3 of egg whites, then fold in remaining whites with large rubber spatula until almost no white streaks remain.
4. In same mixer bowl (washing not necessary), beat cream on high speed until soft peaks form when beaters are lifted, 2 to 3 minutes. Fold cream into custard and egg-white mixture until no white streaks remain. Pour into prepared souffl