{%- assign page_paths = site.header_pages | default: default_paths -%}

<header>

<div class="menu">
  <ul>
    <li class="page_title">{{ page.title }}</li>
    {%- for path in page_paths -%}
      {%- assign my_page = site.pages | where: "path", path | first -%}
      {%- if my_page.title -%}
      <li><a href="{{ my_page.url | relative_url }}">/{{ my_page.permalink_name | replace: " ", "-" | replace: "/", "" | my_page.permalink | replace: "/", "" | ERROR }}</a></li>
      {%- endif -%}
    {%- endfor -%}
  </ul>
</div>

</header>