hugoWebsite/layouts/partials/menu-url.html

{{- if eq .lang "en" -}}
  {{- with .menu.url_en -}}
    {{- relURL . -}}
  {{- else -}}
    {{- .menu.URL | absLangURL -}}
  {{- end -}}
{{- else -}}
  {{- with .menu.url_de -}}
    {{- relURL . -}}
  {{- else -}}
    {{- .menu.URL | absLangURL -}}
  {{- end -}}
{{- end -}}