How to dynamically remove CRUD in SonataAdminBundles route parameter

Question

What i'm trying to do is to remove the create action when there is already a database entry. This entry just needs to be editable or deletable, and don't want the user to be able to create anymore. If he deletes this unique entry, the create button has to reappear.

protected function configureRoutes(RouteCollection $collection)
{
    if ($this->hasFavorite())
    {
        $collection->remove('create');
    }
}

hasFavorite() simply returns true/false according to the fact there's an entry in the database or not. In theory, if hasFavorite() returns true, the create action should disappear, but it doesn't.

I think the problem here is with the cache, keeping the initial route. Despite every scenario, the only CRUD I'll get is the first it put in cache. The only solution I found is to manually delete the sonata cache folder when the method is called, which seems to be a bit excessive.

Any idea to make it better ?