Display custom fields too in recent posts widget

You could write your own code for the top of your sidebar.

This is untested, but it should be a good start:

<aside id="custom-recent-posts" class="widget">
    <h1 class="widget-title">Recent Posts</h1>
    <ul>
      <?php
      $postslist = get_posts('numberposts=5');
      foreach ($postslist as $post) {
        setup_postdata($post); ?>
        <li>
          <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a><br/>
          <?php echo get_post_meta($post,'your_first_field;, false') . '<br/>';
                echo get_post_meta($post,'your_first_field;, false');
          ?>
        </li>
     <?php } ?>
    </ul>
  </aside>

You may need to adjust it for styling – also, I assumed you’d want the post titles to output as links.

It won’t work in a text widget.

You’ll want to add it into your sidebar.php file, right before your widgets are called.

Just make sure you’re doing all of this in a child theme so it’s update proof! 🙂

Try framework/functions/theme_sidebar.php but please note that usually youre asked to contact the place you bought the theme from (in this case themeforest) for support for paid themes.

Allowing php in widgets is not something I (or many others) would recommend, instead why dont you take this opportunity to learn some basic plugin programming to make your own widget/widebar plugin?

Then I suggest you write your own recentposts plugin. Information and a basic example is available at:
http://codex.wordpress.org/Widgets_API