A more Perlish way of writing that would be

sub aaa {
    map {
      my $new_widget = $mw->Frame()->pack(-side=>top);
      $new_widget->Label(-text=>"Variable")->pack(-side=>left, -padx=>
+5, -pady=>5);
      $new_widget->Entry(-width=>30)->pack(-side=>left, -padx=>5, -pad
+y=>5);
      $mw->update;
      $new_widget;
    } 1 .. $entry_amount->get;
}
[download]

Now the sub returns a list of widgets.