I think you could probably use kale - but you wouldn't want to cook it as long. In the recipe there are a couple of different steps and you end up cooking the collards for about 6 minutes - I think you'd probably want to do the kale for less - or at least monitor it so it doesn't get too mushy. I love Kale too though - somewhere on this site I posted my favourite Kale recipe ... African Pineapple Peanut Stew! I haven';t cooked with mustard greens yet.
Michelle, I'm at work now so I don't have the book "The Kind Life" with me. This is pretty much what it is though, or what I did (I apologize for any inconsistencies!)
1.) Roast some pine nuts (in my case, almonds) in a dry pan and set aside for later
2.) Wash and remove the stems from a bunch of collards. Let them sit in a collander (you want some water on them when you cook them, so don't dry or spin them.)
3.) Saute 3 minced cloves of garlic in a tablespoon of olive oil until fragrant
4.) Add greens, stir, then cover for 2 minutes
5.) Uncover, stir, and add 2 tablesspoons of balsamic vinegar or shoyu. Recover for 2 minutes
6.) Uncover, stir, add handful of raisins and pine nuts (I didn't put the almonds in until I was done so that they would be supercrunchy) Cover for 2 more minutes.
I served over quinoa and it was awesome! It felt like a really "complete" meal.
2.) Saute