Zend certified PHP/Magento developer

Custom attribute in cart for configurable products

I am trying to show custom attributes in the checkout/cart page. I have created a catalog_attributes.xml and put it in a custom module

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Catalog:etc/catalog_attributes.xsd">
<group name="quote_item">
<attribute name="delivery_due_date"/> <!-- add your custom attribute name -->
</group>
</config>

and then in cart/info/default.phtml I have

<span>due: <?php echo $_item->getProduct()->getData('delivery_due_date');?></span>

This works for simple products but for configurables it shows the attribute from the parent product not that individual child item. Is there a straightforward way of getting the information for the actual product that the customer has selected? Thanks