My problem is that I don’t know how to invoke .Params.banner within my templates. I assumed I could stick it in theme/cupper-theo/layouts/_default/single.html and then put the cascade: banner: within _index.md of the root of the directory. But the image never came up.
That’s basically it. One note: it’s recommended to do site-specific overrides in your site’s layouts directory (I see you come from WordPress, same idea behind child themes, where you don’t want your changes overridden in a theme update).
I was gonna point out updating your /layouts/_default/single.html template to show the banner, but I’m not finding it in your content directory. Please point me to you _index.md with the banner front matter, and we’ll go from there.
I don’t understand what you are asking. It sounded like you tried adding a banner using front matter cascade, but I can’t see where you tried it. If I can’t see what you tried, I can’t correct it or show a way for it to work.
Sorry I don’t understand, maybe someone else can assist.