Направете продукта представен/непредставен с Laravel

Опитвам се да направя функция за представен/непредставен продукт в Laravel 4.2, но получавам грешка

Извикване на недефиниран метод Illuminate\Database\Query\Builder::save()

Това е моята функция на контролера

public function featuredProduct() {

    $product_featured_id = Input::get('featured');

    $product = Product::where('product_id', $product_featured_id);

    Product::where('featured', 1)->update(['featured' => 0]); // make all other products featured -> 0

    $product->featured = 1;
    $product->save();
    return Redirect::to('/admin/products')->with('message', 'Product marked as featured!');
}

И това е формата в изгледа

{{ Form::open(['url' => '/admin/products/feature', 'method' => 'post']) }}

    <div class="form-group">
        <select class="form-control" name="featured">
            <option value="0">Remove from Featured</option>
                @foreach($products as $featured)

                    <option value="{{ $featured->product_id }}" {{ $featured->featured == 1 ? "selected" : ""}}>{{ $featured->title }}</option>
                @endforeach
        </select>
    </div>
    <button type="submit" class="btn btn-primary">Make Product Featured</button>
{{ Form::close() }}

В таблицата с продукти имам колона, която е освен 1 за представен продукт и 0 за непредставен продукт.

Какво пропускам тук?

актуализация:

public function featuredProduct() {

    $product_featured_id = Input::get('featured');

    if($product_featured_id == 0)
    {
        Product::where('featured', 1)->update(['featured' => 0]); // make all other products featured -> 0
    }
    else 
    {
        $product = Product::where('product_id', $product_featured_id)->first();
        Product::where('featured', 1)->update(['featured' => 0]); // make all other products featured -> 0

        $product->featured = 1;
        $product->save();
    }

    return Redirect::to('/admin/products')->with('message', 'Product marked as featured!');
}