Melt white chocolate in a double boiler over medium-low heat, stirring constantly until smooth.

Remove melted chocolate from heat and let cool slightly.

Whip cream until stiff peaks form; set aside.

In a separate bowl, whisk together egg yolks, brandy, and warm water until combined.

Gradually whisk the melted chocolate into the egg yolk mixture until well combined.

Whip egg whites with sugar and vanilla until stiff, glossy peaks form.

Gently fold the egg white meringue into the chocolate mixture using a wooden spoon.

Fold in the whipped cream until just combined, being careful not to overmix.

Ensure the chocolate is cooled to avoid separating the cream.

Blend the mixture lightly until uniform.

Chill the mousse for at least 15 minutes to set before serving.