Figured it out:
/** START The News Feed Dashboard Widget */
add_action('wp_dashboard_setup', 'dfdw_feed_dashboard_add_widgets');
function dfdw_feed_dashboard_add_widgets()
{
$args = array('post_type' => 'dashboard_feed',
'numberposts' => '-1',
);
$loop = new WP_Query($args);
while ($loop->have_posts()): $loop->the_post();
$feed_id = get_post()->ID;
$feed_name = get_field('feed_name');
wp_add_dashboard_widget($feed_name, $feed_name, 'my_cool_widget', null, $feed_id);
endwhile;
}
function my_cool_widget($post, $callback_args)
{
$post_id = $callback_args['args'];
$feed_url = get_field('feed_url', $post_id);
$feed_name = get_field('feed_name', $post_id);
$feed = array(
array(
'url' => $feed_url,
'items' => 5,
'show_summary' => 1,
'show_author' => 0,
'show_date' => 1,
),
);
ob_start(); // start output buffering
wp_dashboard_primary_output($feed_name, $feed);
$buffer = ob_get_clean(); // get the buffer without printing the content
// add the target attribute to the a-tag:
$result = str_replace("<a class="rsswidget"",
"<a class="rsswidget" target="_blank"", $buffer);
echo $result;
}