Output Console.WriteLine from WPF Windows Applications to actual console

Background: I am struggling to add command line and batch processing capabilities to an existing WPF Windows Application. When I detect some options at startup I suppress the window from appearing, do some processing and quit immedietally. Now, because there's no UI I'd like to output some messages to stdout/stderr. Consider following code:

namespace WpfConsoleTest
{
    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            Console.WriteLine("Start");
            System.Threading.Thread.Sleep(1000);
            Console.WriteLine("Stop");
            Shutdown(0);
        }
    }
}

When I run from command line I would expect following output:

Start
Stop

But instead:

C:\test>WpfConsoleTest.exe

C:\test>

You can redirect output, though:

C:\test>WpfConsoleTest.exe > out.txt

C:\test>type out.txt
Start
Stop

Redirecting to CON does not work, unfortunately:

C:\test>WpfConsoleTest.exe > CON

C:\test>

Another problem is that WpfConsoleTest.exe quits immedietaly after start. So:

C:\test>WpfConsoleTest.exe > out.txt & type out.txt

C:\test>

But:

C:\test>WpfConsoleTest.exe > out.txt & ping localhost > nul & type out.txt
Start
Stop

The best solution I was able to come with so far is to use start /B /wait:

C:\test>start /B /wait WpfConsoleTest.exe > out.txt & type out.txt
Start
Stop

This approach is mostly ok - if you wrap it up in a bat you can preserve error code and so on. The one huge downfall is that you get output after application ends, i.e. there's no way you can track progress, you have to wait for whatever is