From page 200 of The Brazilian Table:
2 teaspoons unflavored gelatin
Pinch of salt
1/2 cup plus 2 tablespoons cold water, divided
4 eggs, separated
Juice, zest, and rind of one lime
1/2 cup sugar
1/2 cup cachaca
2 tablespoons confectioners’ sugar
Sprigs of mint for garnish
1. In a small bowl, add the gelatin and a pinch of salt to 1/2 cup cold water and let it sit for 5 minutes for the gelatin to expand.
2. In a medium bowl, whisk the egg yolks until they become creamy. Keep whisking as you add 2 tablespoons water and then the lime juice. Reserve.
3. In a medium-size saucepan heat the gelatin over low heat and mix it to dissolve. Add the sugar at once, stirring well for 2 minutes. Lower the heat and slowly add the egg yolks as you whisk rapidly for 3 minutes.
4. Remove from heat and add cachaca, mixing gently. Add zest of one lime. Fold in gently. Pour the batter into a bowl and allow to cool for 15 minutes.
5. Place the bowl in the freezer for 20 minutes. The gelatin will congeal at the edges of the bowl.
6. Beat the egg whites to a stiff peak. Lightly beat in the confectioners’ sugar.
7. Take the bowl out of the freezer and gently place 1/2 of the egg whites into the bowl. Using a spatula, fold in, making gentle, slow circular movements. Now reverse the p rocess and fold the batter into the egg white bowl, using slow circular movements. The result is a nice light mousse.
8. Take 8 wine glasses and fill 2/3 of each glass with mousse. Place in the refrigerator for 1 hour. Garnish with lime rinds and mint.