How to add Website Title on post's og:title

Website Title: My Awesome Website
Article Title: My first post

It will generate <meta property="og:title" content="My first post">
But I want it be: <meta property="og:title" content="My first post - My Awesome Website">
What should I do?

I found related config on GitHub, but it seens a part of Hugo, I don’t know how to modify.

To override Hugo’s embedded Open Graph template, copy the source code to a file with the same name in the layouts/partials directory, then call it from your templates using the partial function:

{{ partial "opengraph.html" . }}