Route::get() is returning a Illuminate\Routing\Route, so you would be calling icon() on Route not the Router.

If you wanted to extend the Router try looking at the newRoute method, which creates the new Route objects. Perhaps you can have that method using your extended version of Route, where you have added the icon method.

Hmm.. but on the Illuminate\Support\Facades\Route facade the getFacadeAccessor method is returning 'router' which is bound to Illuminate\Routing\Router ?

I'm trying to replace this binding but my replacement doesnt seem to be working properly.

Looks like that is being bound via Illuminate\Foundation\Application@registerBaseServiceProviders -> Illuminate\Routing\RoutingServiceProvider@register -> @registerRouter.