cheese=cabrales
tomato=orlando
mass=secret

##</code><code>##

use strict;
use warnings;
use Config::Tiny;

my $ini = Config::Tiny->new;
my $outfile = 'pizza.ini';
 
my %data = (
  'cheese'   => 'cabrales',
  'tomato'   => 'orlando',
  'mass'     => 'secret',
  'USERNAME' => $ENV{'USERNAME'},
);

$ini->{'MySectionName'} = {}; # new section

while( my ($key, $val) = each %data ) {
  $ini->{'MySectionName'}->{ $key } = $val;
}

$ini->write($outfile, 'utf8');

##</code><code>##

[MySectionName]
USERNAME=
cheese=cabrales
mass=secret
tomato=orlando

##</code><code>##

use strict;
use warnings;
use feature qw/ say /;
use Data::Dumper;

my %data = (
  'foo'    => 'bar',
  $cheese => 'cabrales',
  'USERNAME' => $ENV{'USERNAME'}
);

say Dumper( %data );

##</code><code>##

use strict;
use warnings;
use feature qw/ say /;
use Data::Dumper;

my %data = (
  'foo'    => 'bar',
  '$cheese' => 'cabrales',
  'USERNAME' => $ENV{'USERNAME'}
);

say Dumper( \%data );