engine/app/models/extensions/page/render.rb

module Models  
  module Extensions    
    module Page      
      module Render

        def render(context)
          self.template.render(context)

          if self.layout
            self.layout.template.render(context)
          else
            ::Liquid::Template.parse("{{ content_for_layout }}").render(context)
          end
        end
        
      end      
    end    
  end  
end