<span class=“post-date”>

{{ site.data.settings.post_date_prefix }}
{% assign d = page.date | date: "%-d"  %}
{{ page.date | date: "%B" }}
{% case d %}
  {% when '1' or '21' or '31' %}{{ d }}st
  {% when '2' or '22' %}{{ d }}nd
  {% when '3' or '23' %}{{ d }}rd
  {% else %}{{ d }}th{% endcase %},
{{ page.date | date: "%Y" }}
by
{% if page.author %}
  {{ page.author }}
{% else %}
  {{ site.author }}
{% endif %}

</span>