laravel / cashier just does not use this feature. You are out of luck, as it is easy to just use the Stripe API, which should be loaded as a dependency in your vendor folder. If not, you can simply download it using the composer.
composer require stripe/stripe-php 2.*
You can use it with
use \Stripe\Plan; Plan::create(array( "amount" => 2000, "interval" => "month", "name" => "Amazing Gold Plan", "currency" => "usd", "id" => "gold") );
You can read more here - https://stripe.com/docs/api#create_plan
Goddard
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