Glad that I have found this

What to say? I discovered this plugin just a couple of days ago, and I have the very serious impression that it gives you everything you ever might want from a ‘Posts in the sidebar’ plugin.

Especially nice: You can paste-in your custom CSS to one widget instance and the other instances will inherit it! (But you can also limit one CSS to one instance, if you want.)

Edit: Forgot to mention that it seems to work perfectly with Polylang. Great!