To make Custard: Whisk yolks with sugar in bowl 2 minutes, or until thick and pale yellow in color. Bring milk to a boil in medium saucepan. Whisk 1/2 cup hot milk into egg mixture until blended. Whisk in remaining milk in steady stream until smooth. Return mixture to saucepan, and cook over medium-low heat 5 minutes, or until thickened but not boiling, stirring constantly. Strain into clean bowl, cool, then stir in vanilla.

To make Meringue Islands: Line baking sheet with 2 layers paper towels. Beat egg whites with electric mixer on low speed 2 minutes, or until frothy. Add 2 tablespoons sugar and pinch salt, increase speed to medium, and beat 1 minute, or until meringue begins to turn white. Add 2 tablespoons sugar, and beat 2 minutes more. Add remaining sugar, and beat 4 to 5 minutes, or until firm peaks form. Beat in vanilla extract until just combined.

Bring 1 inch water to a simmer in large skillet over medium heat. Using 2 soupspoons, scoop and scrape 6 dollops of meringue into simmering water. Poach 1 minute. Flip meringues, and poach 1 minute more, or until puffy and firm. Transfer to prepared baking sheet, and repeat with remaining egg white mixture to make 18 meringues. Cool.

Ladle 1/2 cup Custard into each of 6 shallow serving bowls. Float 3 Meringue Islands atop each serving. Sprinkle with nutmeg, and drizzle with caramel sauce, if using.