This post explains how to do it:
(How did I do that? Using Google+'s new embed feature. Do you like it? Should I make more quick-tips like this?)
Something I haven't been able to figure out yet is whether this happens for all posts (including edits of existing posts) or just for newly published posts. If it's the former, then getting your posts right before you publish them is probably more important than ever.
Thanks for reading: How to automatically share every Blogger post you publish on your Google+ page or profile, Sorry, my English is bad:)