WARN - Found no layout

Hello everyone. I’ve got a restaurant theme I’m working on…so I have a menu page that I want to create.

The first version (as I’m still getting acquainted with HUGO) simply ranges through all the .md files in folder /menu

So here is my setup:
I have 3 .md files in subfolder content/menu with an _index.md with this:

---
title: "Menu"
description: "In cursus turpis massa tincidunt dui ut ornare lectus sit. Quam elementum pulvinar etiam non quam lacus."
layout: menu
---

I have menu.html that acts like a list page with this in in there:

{{ define "main" }}
<div class="container">
<h1 class="display-6">Menu</h1>
{{ range .Pages }}
  <div class="menu-item">
  <h2 class="menu-title d-inline lead">{{.Title}}</h2>
  <span>({{.Params.amount}} pieces)</span>
  <span class="float-right">{{.Params.price}}</span>
  <div class="menu-description">{{.Description}}</div>
</div>
{{ end }}
</div>
</div>
{{ end }}

Yet I’m getting this in the terminal:

WARN 2020/03/21 17:06:41 found no layout file for "HTML" for "page": You should create a template file which matches Hugo Layouts Lookup Rules for this combination.
WARN 2020/03/21 17:06:41 found no layout file for "HTML" for "page": You should create a template file which matches Hugo Layouts Lookup Rules for this combination.
WARN 2020/03/21 17:06:41 found no layout file for "HTML" for "page": You should create a template file which matches Hugo Layouts Lookup Rules for this combination.

There is an answer to your question.

See: https://discourse.gohugo.io/search?q=found%20no%20layout

I have a menu.html template in _default which is referred in _index.md of the menu folder.

Strangest thing is that the page works perfectly well even with the warnings.