my %Menu = {
  app1 => {
         label => "  A",
         MenuItems => [ @MenuItems ]
       },
  app2 => {
         label => "  B",
         MenuItems => [ @MenuItems ]
       },
  app3 => {
         label => "  C",
         MenuItems => [ @MenuItems ]
  },
};

##</code><code>##

foreach my $app (@sorted_applications) {
      $app = lc $app;
      push @{ $Menu{$app}{MenuItems} }, $app;
}