Preheat the oven to 180°C fan. To make the dressing, put the sunflower seeds on a baking tray and roast in the oven for 6 minutes. They should become golden and very tasty. You may need to give them a little shake and put them back in for another 2 minutes; use your judgement here, as ovens vary.Blitz most of the sunflower seeds into a paste, reserving a handful for sprinkling over at the end. I use an old coffee grinder for this, but a spice grinder or a mortar and pestle should do the job. Put the seed paste into a bowl and add the vinegar, honey and soy or salt, then trickle in the nutty oil, combining it all into a smooth, thick dressing. Taste it and see if you fancy more vinegar or salt or sweetness and adjust the flavour to suit your palate. To make the dressing a little looser, add a small dash of hot water and whisk.For the cabbage, set a steamer (or a colander and a pan lid work too) over a pot of boiling water. Whatever cabbage you are using, cut off the dry end of the stalk. If using Hispi, quarter the cabbage lengthways through its core. If using a regular white cabbage, cut it into manageable wedges, again through the core. Steam for about 10 minutes until it looks rather relaxed and easy to cut through. White cabbage might take closer to 15 minutes.Let it cool down a bit and dress with the sunflower seed paste dressing (I use a brush and dab it on), putting the rest in a little bowl to spoon on extra at the table. Sprinkle the cabbage with the reserved sunflower seeds and serve.