recipe.hbs

<h1>{{title}}</h1>
<ul>
{{#each step in steps itemController='step'}}
  <li>ID: {{step.id}}, Order: {{step.order}}</li>
  <ul>
  {{#each substep in step.substeps}}
    <li>
      <img {{bind-attr src=substep.image}} />
    </li>
  {{/each}}
  </ul>
{{/each}}
</ul>

step_controller.coffee

StepController = Ember.ObjectController.extend
  sortProperties: ['order'],
  sortAscending: true

`export default StepController`