<?php

//ANTES
        $data = $this->Category->with(array(
            'posts'=>function($query){
                $query->select('id','title');
            }, ))->select('id','name')->get()->toArray();

//DESPUES
        $data = $this->Category->with(array(
            'posts'=>function($query){
                $query->with('featured_images')->select('id','title','excerpt');
            }, ))->select('id','name')->get()->toArray();
?>