template-composite-view.php

// underscore template in a php file that is meant to be included on the page so that it becomes an "inline template"
<script id="template-composite-view" type="text/template">
  <h1>I am a Template With Child View</h1>
  <h2>Here they are.</h2>
  <% if( children.length ) { %>
    <% _.each(children, function(child){ %>
      <div id="<%= child.cid %>" class="child-view"></div>
    <% }); %>
  <% } %>
</script>