basic-theme/layouts/_default/single.html

{{/* This will override the default value set in baseof.html; i.e., "{{.Site.Title}}" in the original example */}}
{{ define "title" }}
{{ .Title }} – {{ .Site.Title }}
{{ end }}
{{ define "main" }}
<main>
    <h1>{{ .Title }}</h1>
    {{ .Content }}
</main>
{{ end }}