theme-mnemosyne-hugo/layouts/partials/sidebar.html

<aside>
	<div>
		<div>
			<h3>LATEST POSTS</h3>
		</div>
		<div>
			<ul>
				{{ range first 5 (where .Site.RegularPages "Type" "in" .Site.Params.mainSections) }}
				<li><a href="{{ .RelPermalink }}">{{ .Title }}</a></li>
				{{ end }}
			</ul>
		</div>
	</div>
</aside>