How to use Custom Fields?

When using the recent posts widget on the home page, I’d like custom fields to be available. To instead of using:

<h2><a href=”<?php the_permalink() ?>” title=”<?php echo esc_attr(get_the_title() ? get_the_title() : get_the_ID()); ?>”><?php if ( get_the_title() ) the_title(); else the_ID(); ?></a></h2>

I’d like to

<?php echo get_post_meta($post->ID,’extra_title’,true); ?>

However, this leaves the title area blank.