Change mailer layout in method

The mail method can take a block that passes in a format object.

class MyMailer < ApplicationMailer
  layout 'mailer'
  def password_reset(user)
   # uses the "mailer" layout
  end

  def special
    mail(to: "whomever") do |format|
      format.html { render(layout: false) } # no layout is used
      format.text # use the special.text.erb like normal
    end
  end
end

This article answer to your question. Just specify :layout option in render method.