DOMDocuments are cool, and a really nice way of dealing with HTML in an OO fashion. However, sometimes, we have an HTML string element which we need to add to our Document. Here’s how you do it:

    function createNodesFromHTML(DOMDocument $doc,$str) 
    {
        $nodes = array();
        $d = new DOMDocument();
        $d->loadHTML("<html>{$str}</html>");
        $child = $d->documentElement->firstChild->firstChild;
        while($child) {
            $nodes[] = $doc->importNode($child,true);
            $child = $child->nextSibling;
        }
        return $nodes;
    }


        $dom = new DOMDocument();
        $icon = '<i class="fa fa-remove"></i>'; // This is our string

        $button = $dom->createElement('a');
        $button->setAttribute('href', '/whatever/delete/12345');
        $button->setAttribute('class', 'btn btn-sm btn-danger');
        
        // This is us turning the string(s) into nodes we can add
        $nodes = createNodesFromHTML($dom, $icon);
        $button->appendChild($nodes[0]);
        
        $dom->appendChild($button);
        echo $dom->saveHTML();