As per usual, I tend to find the solution after I ask it.
On home page:
<div class="blog-index">
{% assign post = site.posts.first %}
{% assign content = post.content %}
{% include custom/asides/recent_post.html %}
</div>
In separate document saved to custom/asides/recent_post.html
:
<h2 class="entry-title">
{% if post.title %}
<a href="{{ root_url }}{{ post.url }}" id="recent_post">{{ post.title }}</a>
{% endif %}
</h2>
<div class="entry-content">{{ content | excerpt }}</div>
<a class="btn btn-default" href="{{ root_url }}{{ post.url }}">{{ site.excerpt_link }}</a>
Found solution here: https://gist.github.com/nimbupani/1421828