<!-- BEGIN COPY / PASTE -->
    function recent_posts_shortcode($atts) {
        $atts = shortcode_atts(
            array(
                'number' => 5, // Default number of posts
            ), 
            $atts, 
            'recent-posts'
        );

        $query = new WP_Query(array(
            'posts_per_page' => $atts['number'],
            'post_status' => 'publish',
        ));

        $output = '<ul>';
        while ($query->have_posts()) : $query->the_post();
            $output .= '<li><a href="' . get_permalink() . '">' . get_the_title() . '</a></li>';
        endwhile;
        $output .= '</ul>';

        wp_reset_postdata();

        return $output;
    }
    add_shortcode('recent-posts', 'recent_posts_shortcode');
    <!-- END COPY / PASTE -->