Authenticate against azure ad using certificate in a client credentials flow

I have an API which needs to authenticate against azure ad to obtain an access token for calling another downstream API. When registering an application in azure AD for the caller API, I could either setup a shared secret or a certificate for the API to use as part of its credentials in a client credentials flow . In the past, I had always used a shared secret as it was more convenient and easier to setup. However, using certificate provides stronger security. After spending a few hours of googling and hacking, I was able to setup and use a certificate instead of a shared secret as credentials for the caller API to authenticate against azure AD.