Is there a way to access rendered content in Jekyll?

Is there a way to access rendered content in Jekyll?

Is there any way to access the rendered content of a post in Jekyll?
Here's the scenario: Suppose I wanted to create a blog index page listing
a bunch of posts. Each post uses a different layout (text, photo, tweet,
etc). Is there a way to get Jekyll to render each post with the layout
specified inside of that post and then hand me the rendered content so
that I can put it into a summary page?
(I'm 97% sure I saw this exact question asked and answered somewhere here
on Stack Overflow, but I cannot for the life of me find it. If anyone
could point me to it, I would be most grateful! Of course, original
solutions are also appreciated!)