home-assistant.io/source/_includes/asides/cookbook_navigation.html

<section class="aside-module grid__item one-whole lap-one-half">
  {% assign cookbook = site.cookbook | sort_natural: 'title' %}

  <div class="section">
    <a href="/cookbook">Back to the cookbook</a>
  </div>

  <div class="section">
    <h1 class="title delta">{{page.ha_category}}</h1>
    <ul class="divided">
      {% for recipe in cookbook %} {% if recipe.ha_category == page.ha_category
      %}
      <li>
        {% if recipe.url == page.url %} {{recipe.title}} {% elsif
        recipe.ha_external_link %}
        <a href="{{recipe.ha_external_link}}"
          >{{recipe.title}} <i class="icon-external-link"></i
        ></a>
        {% else %}
        <a href="{{recipe.url}}">{{recipe.title}}</a>
        {% endif %}
      </li>
      {% endif %} {% endfor %}
    </ul>
  </div>
</section>