I recently needed to change the default output also. Here’s how I used this filter to add the post content to the output.
/**
* Customize the Favorites Listing HTML
*/
add_filter( 'favorites/list/listing/html', 'custom_favorites_listing_html', 10, 4 );
function custom_favorites_listing_html($html, $markup_template, $post_id, $list_options) {
$html="
<li class="favorite">
<div class="favorite-image">
" . get_the_post_thumbnail( $post_id, 'our-products' ) . '
</div>
<div class="favorite-wrapper">
<h2 class="favorite-title">
' . get_the_title($post_id) . '
</h2>
<div class="favorite-content">
' . get_post_field('post_content', $post_id) . '
</div>
<a class="btn green-arrow" href="' . get_the_permalink($post_id) . '">View Recipe</a>
</div>
</li>
';
return $html;
}