0_model.rb

class Recipe < ApplicationRecord
  belongs_to :user
end

class User < ApplicationRecord
end

1_controller.rb

class RecipesController < ApplicationController
  def index
    @recipes = Recipe.page(params[:page])
  end
end

2_view.html.erb

<% # recipes/index.html.erb %>
<ul>
  <%= render @recipes %>
</ul>

<% # recipes/_recipe.html.erb %>
<li>
  Title: <%= recipe.title %>
  Author: <%= recipe.user.name %> <!-- here's the N+1 query -->
</li>