After seeing some really nice examples (on Pinterest) of so called "double knitting" (knitting 2 layers at the same time with reversed pattern) I decided to try it myself.
It's just so helpful to have YouTube so you can follow visual instructions step by step.
Turned out it's not near as difficult as it seems but you do need to keep a close eye on your stitches.
I started with a small sample piece with hearts (Valentines Day is coming up!).
Free pattern here
I think I'll try the Christmas blanket again next year but then in the double knit, it's an absolutely perfect technique for that!