I just tried blogger. Never used it before. You can switch to HTML mode when editing a post and just paste the widget code. You can see an example here: https://steemitwidgets.blogspot.de/2017/08/steemitcom-widgets-on-you-blogger-blog.html
You can also add "Sidebar Gadgets" of type "HTML/Javascript" in the Layout settings. It works to. I display my recent steemit posts this way on the left hand side of the example page.