hugo-theme-flat/layouts/partials/side-recent.html

<div class="side-recent">
    <h2 class="side-title">
        <a href="{{ .RelPermalink }}">Recent {{ .Section | humanize }}</a>
    </h2>
    <hr />

    <ul>
        {{ range first 5 .RegularPages.ByDate.Reverse }}
            <li>
                <a href="{{ .RelPermalink }}">{{ .Title }}</a>
            </li>
        {{ end }}
    </ul>
</div>