Not sure this qualifies as more elegant, or just more obfuscated than rev_1318's solution.

use YAML;

my %h = (
'accesslevels' => {
  'function' => {
    'func1'   => { 'content' => 'val1' },
    'default' => { 'content' => 'val2' }
  }
},
'accesslevels2' => {
  'function' => {
    'func1'   => { 'content' => 'val1' },
    'default' => { 'content' => 'val2' }
  }
});

for my $L (values %h) {
  my (%tmp, $k, $v);
  for (values %$L) {
    $tmp{$k} = $$v{content} while ($k,$v) = each %$_;
  }
  $L = \%tmp;
}

print Dump \%h;
[download]