This one is kind of easy, but tricky.
In “summary.html”
{{ if .Truncated }}
{{ .Summary | safeHTML }}
<a href="{{ .Permalink }}#{{ .Title | urlize }}" class="read_more">Read more...</a>
{{ else }}
{{ .Content}}
{{ end }}
In “single.html”
<article>
<a name="{{ .Title | urlize }}"></a>
{{ . Title }}
{{ .Content }}
...
That’s it. When you do your <!--more-->
guess what’s going to happen? You are going to get the title’s ID as an anchor text before your Title in the single version of the page.
Boom.