ob_start <> eval?

I have a template system that takes some data, scrubs it and then with a load method includes the required template. I need to add a param so it doesn't simply include but returns the contents of the template in a string with all of the vars populated. I tried: ob_start(); include my template $template=ob_get_contents(); ob_clean(); return $template; But this returns the template it's it's raw for with all of tha <?=$whatever?> tags. Can I fill these in and still pass as another var without using eval()? What do other template systems to do return a template as a string on load? Thanks!