Change ob_get_contents to ob_get_clean, ob_get_contents gets the contents of the buffer but leaves it intact. Your Previous code got the buffer assigned it a variable then, flushed the buffer to output.
function outputContent($var, $errors = null)
{
extract($var);
ob_start();
include 'template-file-for-output.php';
$output = ob_get_clean();
return $output;
}