can't figure out TokenMismatchException

I have this form:

<form method = "POST" action = "/show">
                        <div class = "formgroup">
                            
                            <textarea name = "ASIN" class = "form-control"></textarea>
                        </div>
                        <div class = "formgroup">
                            <button type = "submit" class = "btn btn-primary">look-up</button>
                        </div>
                    </form>

...and this route: Route::post('/show', 'ShowController@show'); and this controller:

class ShowController extends Controller
{
    public function show(Request $request)
    {
        return $request->all(); 
    }
}

(right now I am just trying to see if the info from my textarea is showing up in my /show page)

I am getting the following error:

TokenMismatchException in VerifyCsrfToken.php line 67:
in VerifyCsrfToken.php line 67
at VerifyCsrfToken->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in ShareErrorsFromSession.php line 49
at ShareErrorsFromSession->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in StartSession.php line 64
at StartSession->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in AddQueuedCookiesToResponse.php line 37
at AddQueuedCookiesToResponse->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in EncryptCookies.php line 59
at EncryptCookies->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in Pipeline.php line 104
at Pipeline->then(object(Closure)) in Router.php line 644
at Router->runRouteWithinStack(object(Route), object(Request)) in Router.php line 618
at Router->dispatchToRoute(object(Request)) in Router.php line 596
at Router->dispatch(object(Request)) in Kernel.php line 267
at Kernel->Illuminate\Foundation\Http\{closure}(object(Request)) in Pipeline.php line 53
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in CheckForMaintenanceMode.php line 46
at CheckForMaintenanceMode->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in Pipeline.php line 104
at Pipeline->then(object(Closure)) in Kernel.php line 149
at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 116
at Kernel->handle(object(Request)) in index.php line 53
at require_once('C:\Users\Mike\indie\public\index.php') in server.php line 21

I've checked my spelling and syntax and don't see anything wrong. Any idea?