CFML was the easiest way to get into dynamic, server-side rendered pages back in the day. It was insanely productive and easy for a person cutting their teeth on programming as it was such a small leap from HTML.

I don't know of anything that still ticks those boxes but if you're just looking for (1) easy-ish, (2) interspersing HTML tags and code, and (3) server-side rendered simplicity, then PHP is still a very viable successor.