Following Stephan's previous advice, I've been harvesting my seakale for the last six weeks or so: I'm eating it unblanched in stir frys, curries, salads...But I think most people would want to blanch it.
It's a very tasty, interesting-looking, hardy and under-rated vegetable. A bit like myself.
Plant the roots a stride apart and forget about them until spring. (But try not to plant your parsley on top of them like I did.) I put my seakale in a perennial bed with globe artichokes, which is kind of posh isn't it?