if you want smoother transition, try my approach: code with Java style (OOP, imperative) but using Scala syntax. once you're familar with the new syntax, naturally you will wonder, "this seems clunky, there's got to be a way to do this the Scala way". and you'll start googling "how to do X in a list" etc.

to lower the bar, don't use framework. i even coded http://ngajakjalan.com (one of my projects written in Scala) without framework, just plain servlet+JSP. again, eventually you'll think, "i keep doing the same thing, there's got to be some library out there already doing this for me", and start exploring.