Scrape the seeds out of the vanilla bean and combine with the liqueur in a small saucepan. Sprinkle the gelatin on top and let stand 5 minutes. Add 1/2 cup heavy cream and cook over low heat, stirring, until the gelatin dissolves. Add the white chocolate and continue to cook, stirring, until melted. Transfer to a large bowl; let cool 25 minutes.
Beat the egg whites and cream of tartar in a large bowl with a mixer on medium-high speed until stiff peaks form, about 4 minutes. Fold the egg whites into the white chocolate mixture until almost incorporated. Add the remaining 3/4 cup cream to the mixer bowl and beat on medium-high speed until medium peaks form; fold into the white chocolate mixture until incorporated. Divide among small bowls. Refrigerate until set, at least 3 hours or overnight. Top with shaved chocolate.