I'm a vegetarian so I'm hardly going to make this these days for me so hence the 4 stars rather than the 5 stars. But I'm sure this recipe would go down extremely well. Mashing the kale and potato together is essential. I have never seen oats used so this is a less essential step. As a vegetarian I now cook the rookworst separately when I make this for my FIL because kale is one of my favourite cold climate comfort foods. I like to add lots of butter to my portion of the mash. Dad used to add a touch of white vinegar at the table. I have never tried mustard and nutmeg with this but I would expect it to be good,particularly the mustard.FIL doesn't seem to protest this version that's for sure!