Not displaying Breakfast recipes

<?php
include"classes/recipes.php";
include"classes/render.php";
include"classes/recipecollection.php";
include"inc/recipes.php";


$cookbook=new RecipeCollection("Treehouse Recipes");
$cookbook->addRecipe($lemon_chicken);
$cookbook->addRecipe($dried_mushroom_ragout);
$cookbook->addRecipe($rabbit_catalan);
$cookbook->addRecipe($grilled_salmon_with_fennel);
$cookbook->addRecipe($pistachio_duck);
$cookbook->addRecipe($chili_pork);
$cookbook->addRecipe($crab_cakes);
$cookbook->addRecipe($beef_medallions);
$cookbook->addRecipe($silver_dollar_cakes);
$cookbook->addRecipe($french_toast);
$cookbook->addRecipe($corn_beef_hash);
$cookbook->addRecipe($granola);
$cookbook->addRecipe($spicy_omelette);
$cookbook->addRecipe($scones);

$breakfast=new RecipeCollection("Favorite Breakfasts");

foreach($cookbook ->filterByTag("breakfast") as $recipe){
    $breakfast->addRecipe($recipe);
}


//var_dump($cookbook);
echo Render::listRecipes($breakfast->getRecipeTitles());

//echo Render::displayRecipe($belgian_waffles);


?>

<?php

class RecipeCollection{
    private $title;
    private $recipes =array();

    public function __construct($title=null){
        $this->setTitle($title);
    }

    public function setTitle($title)
    {
        if(empty($title)){
            $this->title=null;
        }else{
            $this->title=ucwords($title);
        }  
    }

    public function getTitle()
    {
        return $this->title; 
    }

    public function addRecipe($recipe){
        $this->recipes[]= $recipe;
    }

    public function getRecipes()
    {
        return $this->recipes;
    }

    public function getRecipeTitles(){
        $titles=array();
        foreach($this->recipes as $recipe){
            $titles[]=$recipe->getTitle();
        }
        return $titles;
    }

    public function filterByTag($tag){
        $taggedRecipes=array();

        foreach($this->recipes as $recipe){
            if(in_array(strtolower($tag), $recipe->getTags())){
                $taggedRecipes[]=$recipe;
            }
            return $taggedRecipes;
        }


    }


}

?>