blog/_src/_includes/featured.html

<aside class="grid featured">
    {% for post in site.posts %}
        {% if post.featured %}
        <article class="col2">
            <a class="featured-link" href="{{ post.url }}" title="{{ post.title }}">
                {% picture featured {{ post.image }} %}
                <h1 class="featured-title">{{ post.title | titlecase }}</h1>
            </a>
        </article>
        {% endif %}
    {% endfor %}
</aside>